Amazon S3 Stream Wrapper

Similar work has been completed with Media : Amazon
http://drupal.org/project/media_amazon

Amazon S3 is storage for the Internet. It is designed to make web-scale computing easier for developers.

Amazon S3 has a simple web services interface that can be used to store and retrieve any amount of data, at any time, from anywhere on the web. It gives any developer access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of web sites. The service aims to maximize benefits of scale and to pass those benefits to developers.

Amazon S3 PHP class

This class is a standalone Amazon S3 REST implementation for PHP 5.2.x (using CURL), that supports large file uploads and doesn't require PEAR.
Checkout the latest

S3 Api guide

/**
 * @param object $file
 * example :
 *  $file = new stdClass();
 *  $file->uid      = $user->uid;
 *  $file->filename = $filename;
 *  $file->filepath = $filepath;
 *  $file->filemime = file_get_mimetype($filename);
 *  $file->filesize = filesize($filepath)
 *  $file->timestamp = time();
 * 
 */

/**
 * sends file to s3
 * @param array $file standard file object
 * @returns string completed file string
 *
 */
s3_api_put_file($file);

/**
 * get a file path
 * @param object $file
 * @return path to file
 */
s3_api_get_file($file);

/**
 * deletes files from the amazon system
 * @param object $file
 * @return bool 
 */
s3_api_delete_file($file);