diff --git a/src/HPCloud/Transport/CURLTransport.php b/src/HPCloud/Transport/CURLTransport.php
index 9218bb3..743b966 100644
--- a/src/HPCloud/Transport/CURLTransport.php
+++ b/src/HPCloud/Transport/CURLTransport.php
@@ -8,11 +8,137 @@ namespace HPCloud\Transport;
 
 /**
  * Provide HTTP transport with CURL.
+ *
+ * You should choose the Curl backend if...
+ *
+ * - You KNOW Curl support is compiled into your PHP version
+ * - You do not like the built-in PHP HTTP handler
+ * - Performance is a big deal to you
+ * - You will be sending large objects (>2M)
+ * - Or PHP stream wrappers for URLs are not supported on your system.
+ *
+ * CURL is demonstrably faster than the built-in PHP HTTP handling, so
+ * ths library gives a performance boost. Error reporting is slightly
+ * better too.
+ *
+ * But the real strong point to Curl is that it can take file objects
+ * and send them over HTTP without having to buffer them into strings
+ * first. This saves memory and processing.
+ *
+ * The only downside to Curl is that it is not available on all hosts.
+ * Some installations of PHP do not compile support.
  */
 class CURLTransport implements Transporter {
 
   public function doRequest($uri, $method = 'GET', $headers = array(), $body = '') {
 
+    $in = NULL;
+    if (!empty($body)) {
+      // First we turn our body into a temp-backed buffer.
+      $in = fopen('php://temp', 'wr', FALSE);
+      fwrite($in, $body, strlen($body));
+      rewind($in);
+    }
+    return $this->handleDoRequest($uri, $method, $headers, $in);
+
+  }
+
+  public function doRequestWithResource($uri, $method, $headers, $resource) {
+    if (is_string($resource)) {
+      $in = open($resource, 'rb', FALSE);
+    }
+    else {
+      $in = $resource;
+    }
+    return $this->handleDoRequest($uri, $method, $headers, $resource);
+  }
+
+  /**
+   * Internal workhorse.
+   */
+  protected function handleDoRequest($uri, $method, $headers, $in = NULL) {
+
+
+    // Write to in-mem handle backed by a temp file.
+    $out = fopen('php://temp', 'w');
+
+    $curl = curl_init($uri);
+
+    // Set method
+    $this->determineMethod($curl, $method);
+
+    // Set headers
+    $this->setHeaders($curl, $headers);
+
+    // Set the upload
+    if (!empty($in)) {
+      curl_setopt($curl, CURLOPT_INFILE, $in);
+    }
+
+    // Get the output.
+    curl_setopt($curl, CURLOPT_FILE, $out);
+
+    curl_exec($curl);
+
+    // Now we need to build a response.
+    // Option 1: Subclass response.
+    // Option 2: Build an adapter.
+
+    curl_close($curl);
+
+    fclose($in);
+  }
+
+  /**
+   * Set the appropriate constant on the CURL object.
+   *
+   * Curl handles method name setting in a slightly counter-intuitive 
+   * way, so we have a special function for setting the method 
+   * correctly. Note that since we do not POST as www-form-*, we 
+   * use a custom post.
+   *
+   * @param resource $curl
+   *   A curl object.
+   * @param string $method
+   *   An HTTP method name.
+   */
+  protected function determineMethod($curl, $method) {
+    $method = strtoupper($method);
+
+    switch ($method) {
+      case 'GET':
+        curl_setopt($curl, CURLOPT_HTTPGET, TRUE);
+        break;
+      case 'HEAD':
+        curl_setopt($curl, CURLOPT_NOBODY, TRUE);
+        break;
+
+      // Put is problematic: Some PUT requests might not have
+      // a body.
+      case 'PUT':
+        curl_setopt($curl, CURLOPT_PUT, TRUE);
+        break;
+
+      // We use customrequest for post because we are
+      // not submitting form data.
+      case 'POST':
+      case 'DELETE':
+      case 'COPY':
+      default:
+        curl_setopt($curl, CURLOPT_CUSTOMREQUEST, TRUE);
+    }
+
+  }
+
+  public function setHeaders($curl, $headers) {
+    $buffer = array();
+    $format = '%s: %s';
+
+    foreach ($headers as $name => $value) {
+      $buffer[] = sprintf($format, $name, $value);
+    }
+
+    curl_setopt($curl, CURLOPT_HTTPHEADER, $buffer);
   }
 
 }
diff --git a/src/HPCloud/Transport/PHPStreamTransport.php b/src/HPCloud/Transport/PHPStreamTransport.php
index 127860f..fa1fa7e 100644
--- a/src/HPCloud/Transport/PHPStreamTransport.php
+++ b/src/HPCloud/Transport/PHPStreamTransport.php
@@ -73,6 +73,60 @@ class PHPStreamTransport implements Transporter {
     return $response;
   }
 
+  /**
+   * Implements Transporter::doRequestWithResource().
+   *
+   * Unfortunately, PHP Stream Wrappers do not allow HTTP data to be read
+   * out of a file resource, so using this method will allow some
+   * performance improvement (because grabage collection can collect faster),
+   * but not a lot.
+   *
+   * While PHP's underlying architecture should still adequately buffer large
+   * strings, the effects of this buffering on really large data (5G or so)
+   * is unknown.
+   */
+  public function doRequestWithResource($uri, $method, $headers, $resource) {
+
+
+    // In a PHP stream there is no way to buffer content for sending.
+    // XXX: Could we create a class with a __tostring that read data in piecemeal?
+    // That wouldn't solve the problem, but it might minimize damage.
+    if (is_string($resource)) {
+      $in = fopen($resource, 'rb', FALSE);
+    }
+    else {
+      $in = $resource;
+    }
+    $body = '';
+    while (!feof($in)) {
+      $body .= fread($in, 8192);
+    }
+
+    $cxt = $this->buildStreamContext($method, $headers, $body);
+    $res = @fopen($uri, 'rb', FALSE, $cxt);
+
+    // If there is an error, we try to react
+    // intelligently.
+    if ($res === FALSE) {
+      $err = error_get_last();
+
+      if (empty($err['message'])) {
+        throw new \HPCloud\Exception("An unknown exception occurred while sending a request.");
+      }
+      $this->guessError($err['message'], $uri, $method);
+
+      // Should not get here.
+      return;
+    }
+
+    $metadata = stream_get_meta_data($res);
+
+    $response = new Response($res, $metadata);
+
+    return $response;
+
+  }
+
   /**
    * Given an error, this tries to guess the cause and throw an exception.
    *
diff --git a/src/HPCloud/Transport/Transporter.php b/src/HPCloud/Transport/Transporter.php
index dfd70a2..5e4f45f 100644
--- a/src/HPCloud/Transport/Transporter.php
+++ b/src/HPCloud/Transport/Transporter.php
@@ -1,5 +1,6 @@
 <?php
 /**
+ * @file
  * This file contains the interface for transporters.
  */
 
@@ -38,4 +39,38 @@ interface Transporter {
    *   The string containing the request body.
    */
   public function doRequest($uri, $method = 'GET', $headers = array(), $body = '');
+
+
+  /**
+   * Perform a request, but use a resource to read the body.
+   *
+   * This is a special version of the doRequest() function.
+   * It handles a very spefic case where...
+   * 
+   * - The HTTP verb requires a body (viz. PUT, POST)
+   * - The body is in a resource, not a string
+   *
+   * Examples of appropriate cases for this variant:
+   *
+   * - Uploading large files.
+   * - Streaming data out of a stream and into an HTTP request.
+   * - Minimizing memory usage ($content strings are big).
+   *
+   * Note that all parameters are required.
+   *
+   * @todo Declare this in Transporter.
+   *
+   * @param string $uri
+   *   The target URI.
+   * @param string $method
+   *   The method to be sent.
+   * @param array $headers
+   *   An array of name/value header pairs.
+   * @param mixed $resource
+   *   The string with a file path or a stream URL; or a file object resource.
+   *   If it is a string, then it will be opened with the default context.
+   *   So if you need a special context, you should open the file elsewhere
+   *   and pass the resource in here.
+   */
+  public function doRequestWithResource($uri, $method, $headers, $resource);
 }