If I "refer" you, both of us get an extra 250MB of space. So if you plan on signing up and you want 2.25gigs instead of 2gigs, click here:
https://www.dropbox.com/referrals/NTY0MjU0Mzk5
Again, you don't have to, and I wouldn't post it if it only helped me... but this will actually help everyone who uses it... and I would suggest being referred to the site over just signing up.
For those who aren't sure what Dropbox is, Dropbox enables you to have a single "folder" on your desktop that syncs with the dropbox website. Your phone can then access the website and retrieve all of the files. If you update a file on your phone, it pushes the update online, and your computer will update accordingly with the newer file. If you update a file on your computer, the dropbox website updates with the newer file... and you can then retrieve that file with your Android smartphone. It also has a "shared" folder that you can share with friends. You can also have a Dropbox folder on multiple computers (I have one on both work computers, a Mac + a PC, my Incredible, and my Omnia).
P.S. Check THIS out:
The Android intro tutorial lists one interesting feature:
Launch your phone’s built-in camera
while running Dropbox and your
photos and videos will upload to your
Dropbox instantly. When you use this
feature together with Dropbox shared
folders, these files are synced to your
friends’ and family’s computers
instantly!
I expect this is going to be many people's most popular use of Dropbox.
The Dropbox to install on your Android is in the market BTW