If you’ve never used Dropbox, it is a cross-platform cloud sync application that keeps your files up-to-date in a “dropbox.” Whatever you put in this My Dropbox directory will be synced into the cloud without user intervention.

It is available for Windows, Mac, Linux, iPhone and now Android (Blackberry is coming soon).

Free accounts get 2GB data and up to 3GB free with referrals. Price plans start at $9.99US/month. For peace of mind, I can’t imagine a better utility. It’s rivaled by SugarSync and Zumodrive, both of which have iPhone and Android clients, though Dropbox seems to be the big kahuna of the industry, most likely due to its versatility.

On the Android app, though auto-sync is not yet available, you can upload files directly from your phone, view and edit documents in the app, and view photos streamed from the cloud. There is no MP3 streaming support just yet, but that will hopefully come in time.

Search for Dropbox in the Android Marketplace, or head to their website for more information.