There is this new product released in Google Solutions Marketplace - Google Docs Backup.
I find it amusing.
Firstly, if one decides to go with Google Apps, then he must be attracted by the Cloud and the convenience of accessing it anytime, anywhere. (Not not being restricted to his desktop)
Secondly, if one does not feel comfortable (in terms of security and "safe-ness" of one's data) with hosted service (that's what cloud is), then one should not even jump into the wagon.
Why would you need to backup your Cloud data? Strange. Dun tell me the data in the Cloud does not have redundancy and backup in place?