bill - 2:53 am on Nov 7, 2008 (gmt 0) sync
I've heard too many bad things about those settings transfer programs. I've always found it a good investment of time to do it manually. Especially in a case like this where you have XP and Vista. Those two OSs are quite different. They sometimes need different software from one another. Take the time and do it yourself.
That depends on what you want to sync. Microsoft has a couple of offerings (both free) that can help: FolderShare and the new beta Live Mesh. FolderShare is quite stable, but it's limited to a certain number of files and folders. Live Mesh is awesome. It will sync almost everything. It's beta though.