Am surprised no one has mentioned it yet so i might as well.
FB1.9 for BB is out and its faster with a 'search facebook' function though it hasn't worked 100% for me when it comes to people search. RIM also claims it has the option for inbox integration (like twitter for bb) though i don't see an option anywhere for it so i'm guessing it's a os6 option only. over all it's faster under os5 and that's always a good thing
The only way to d/l it is u have to register for the blackberry.com/beta program. Takes a couple of minutes then an additional couple of mins for the activation code and ur facebookin'