If you've got a Gmail account, you've got handy access to 1gb of email, and now most accounts also have POP access enabled. Using those two facts, forum reader minton created a script that backs up selected files from the Finder to a Gmail account.
I haven't tested this one yet, so no promises, but it looks interesting.
Mac OS X Hints
http://hints.macworld.com/article.php?story=2004120705364584