I've been looking at online backup options for the WHS server for offsite disaster recovery.
While such services were mostly prohibitivly expensive a year ago, I found a couple of newer companies that provide online storage (not file sharing etc.) for a very reasonable fee. I looked specifically at Mozy and Carbonite as they offer the best deals and seem to have decent VC backing.
Mozy has the best reviews, but unfortunately, requires the more expensive Pro version to backup Windows 2003/WHS servers. Carbonite has been working well for the last week or two and I've test-restored a few files without a problem. Both the services work very quietly in the background.
IMO, a service like these two (and at these prices) would be indispensible as part of the Windows Live addon to WHS.