Starting today, you can share photos, documents, and other files while chatting in iGoogle and Orkut. Just click Send a file... in the Actions menu while chatting with a friend (no download required).
This feature is also compatible with the file transfer functionality in the Google Talk downloadable software, so you can share files directly from the web with folks who use the desktop version.
File transfer is available in Orkut and iGoogle only for now. But Gtalk team is working on bringing it to Gmail as well.