My advice is that you put off installing Nitdroid as long as possible. You don't need it; it won't give you a better device; and it can get you in a lot of trouble.

As far as backups go -- there are two backup programs, Backup and Backupmenu. The first comes from Nokia; the last is better, faster, easier, and more complete. (I personally use both, but when it comes to restoration, I almost always rely on Backupmenu.)