http://forums.dropbox.com/topic.php?id=52900
Basically use the beta client to upload photos and movies and you'll get free space on dropbox.
I just tried it and it's working great, I just took an SD card, put a DCIM folder on it (just in case), copied a bunch of photos to it, eject, insert, dropbox asks if I want to import, say yes, and away it went.