I'm really sorry, if I missed it somewhere but I cant find the source for the swf files. I'd like to change the path to the upload file as absolute (ie) an external url. The way it is right now doesnt make much sense if the swf files are loaded on a shared resources server (so that they are cached) while the upload script is on one of the clustered servers.
Complete source included
The complete source code has been included in all releases and beta of SWFUpload. You'll find it in the .as files.
SWFUpload was coded and compiled using FlashDevelop. The SWFUpload package includes a the FlashDevelop project files as well.