Are you on a Mac, Snaggletooth? Preview will let you re-save a JPEG with more compression (ie. smaller file size). Image quality will suffer a bit, but you can make the file smaller.
If you are on a PC (or a Mac and want more features than what Preview has to offer), you can visit
http://www.sumopaint.com/ . Sumo Paint is a Flash-based image editor, almost as fully featured as Photoshop. Open the image in there and you can re-save it smaller. "Open" and "Save as..." commands are under the "File" menu.
