Always update to the latest firmware

Install rootsh from extras to get root access (RDmode)

You news to enter the repo details in the app manager to get extras and extras devel
Lots of people say don't enable them but as long as your sensible and realise that not everything in here is ready for the end user you'll be ok

Google how to enable extras devel n900
And get the details from there

Install faster application manager and learn to use it as hildon app Mgr is painfully slow