Online backup

A couple of ways you can do this.

Use gmail, save files as attachments. There is a handy download utility that will mount you gmail as a network drive on your pc. This allow you to drag and drop files to your gmail account. Mac , PC

Buy an .mac account. Comes with up to 10gb of storage, depending on how much you allocate to .mac mail. This cost $99/year, however there are a bunch of other services included with a .mac account.

mozy - 4.95/month and you get 2gb of encrypted storage. 30 days before older versions are deleted. - Good if you need to go back to an old copy of a file.

carbonite - 49.95/year, for unlimited space. Data is encrypted and they only keep recent copies.