No setup needed.
You can just go into your address book and highlight your wife's name with the track wheel and click it, scroll down to PIN wife or whatever and click that and your there.
BB messenger is more of an AIM just between Berry's you can collect pins and use it like as your inatant messenger. Pin messages work only between other berrys tho.
However you can get another prog like Ramble im and use that as well. That will allow use of other IM clients such as AIM or google chat I believe.

Any other Q's ask away!
Welcome and good luck with your new Berrys!!!!!!!!