You can try here: Google Mobile - Google Mobile Help
As there are many threads about syncing two calendars. I just have the one.
With each email address you get a calendar in the Blackberry and can assign appointments to it. Why? I haven't a clue nor do I use them. You can delete the service books or just ignore them which is what I do.
Google will sync with your gmail or hosted google email account on the blackberry. I make my google hosted account the blackberry default calendar Options, Advanced Options, Defaults Services.
I like Google and have all my contacts and calendar on Google. For tasks and notes I use rexwireless. So, there really isn't a need for me to backup my BB using desktop manager. I don't know how well yahoo or msn work with the BB but google is the only one that I know of that syncs you contacts and calendar without having to to anything.