Saving WordPress Media to Amazon S3 (Teaser)
I've been thinking about this for a long time, but only now do I have a hacked version of WordPress, a small plugin to modify upload file paths, and a mutilated copy of the Zend S3 client which patches in some necessary functionality. Uploads go directly into S3 without so much as touching wp-content. (OK, the file does touch the local temp directory while uploading, but it doesn't stick around.)
Now, to make it usable.