DrobBox

DropBox is very good which is one of the services that will backup 2GB for free but in unique in that it will allow users to download the software, login to your account and actively edit files on the shared folder. It event uses Growl notification to let everyone know a shared file is being edited or has changed.

DropBox will install a folder on your computer that will backup to the cloud any file you place in that folder. These files can be shared with others.

There is an iPhone app to access your data.

There are many tips on the DropBox website but they are kind of hidden. One tip is that what if you already have a folder on your computer that you would like to backup and share instead of dropping files into the DropBox folder. Easy for us geeks, but the solution is to create a symbolic link to your existing folder. Here is the DropBox tip for this solution.