We've probably all heard of Dropbox. It provides 2gb of free space where you can store files/documents whatever. And there's an Android app for it.
I've used all my 2gb and a friend recommended SugarSync.
SugarSync provides 5gb of free storage. And like Dropbox, you can grow your storage by friends clicking on your link.
SugarSync also has an Android app.
I've used both. I don't have a preference as far as ease of use, but if you share documents/files on Dropbox then that shared information uses space on each machine.
If you share files/documents on SugarSync, then it's only the owners storage that is affected. The size of the file doesn't count towards any other account's storage.
So for an extra 3gb, and knowing shared documents you receive don't add to your own storage use, I'd say SugarSync is better.
If anyone is interested in joining SugarSync and wants my "referral" link (which will give me an extra 500mb of space) then let me know. I wont post my referral link here in case people think this suggestion/recommendation is self gratifying.
More important to me is sharing of information which may provide a useful tool to the SGSII community.