Are referring to the community edition which we supposedly will be able to run on the N900?
I thought the Handset UX was closed source.
Everything that I've heard so far indicates that the reference implementation of MeeGo on the N900 will not be usable for regular users.
Calls in NITDroid are working (the actual sound in the call is being worked on) and I believe a member on the MeeGo forum (he is also a member here) made calls on MeeGo for N900.