I have been using the free version of Mozy for the last year now. I had some hiccups while there were still in beta in the spring but since the summer they have been rock solid. They have just released a service with unlimited backup storage for $4.95/mo. If you have a lot of storage, this is a GREAT deal.

Mossberg also recently gave Mozy a thumbs up.

Click here for the free version of Mozy that will give you 2.5GB of storage.