just so everyone knows - I got an Iphone 4 and the goddamn thing does not fully work with my bimmer
I can call and use phone book and see recent calls but it does NOT support viewing text messages and emails on the navi screen.
I now researched it and apparently the only site that provides proper info re tested phones is BMW UK (and german one).
The phone that seems to work best with bimmer is NOKIA (newer models).
Both BBs and Iphones do not fully work.
Of course noone is dependnt on viewing text messages on screen, but it's a nice option which I lost through buying an Iphone 4.