The Underscore Archives

I am considering setting up an off-site backup repository of my personal 
and business files and I keep hearing about Amazon S3 [1] which actually 
seems like it could work out cheaper than the likes of say Mozy Pro [2]. 
At a rough guess I think I have probably got in the region of 80GB that 
I would want to dump somewhere and then be able to synch to.

I guess my question is...can anyone recommend some software that can do 
the job Mozy seems to do but using Amazon S3 for storage?

[1] http://www.amazon.com/gp/browse.html?node=16427261
[2] https://mozy.com/pro/