Plupload: Multi-runtime File-Uploader

http://www.plupload.com/

Files not only can be picked from browse dialog, but also can be dropped directly from the desktop.

Files that have to be uploaded can be small or huge - about several gigabytes in size. In such cases standard upload may fail, since browsers still cannot handle it properly. We slice the files in chunks and send them out one by one. You can then safely collect them on the server and combine into original file.

(Great stuff, GPL v2 and OEM license available)