I guessing that you need something fairly straight forward and easy.

If you don't and are willing to put some work in you can use rsync to build a network incremental backup system.

http://samba.anu.edu.au/rsync/

I use this to backup my local server to a remote server in a friend's house (via DSL) and I have also used it to backup my laptop when on holiday (via hotel room Internet connections).

Looks like someone has be working on some Mac specific changes to rsync as well:

http://www.bombich.com/mactips/rsync.html