There is no need to take out/reinsert your simcards as of 0.9.4! If your carrier name doesn't appear, turn on/off Flight Mode and you should be fine! :D

Ok, not working for me.. I live in Sweden, carrier is Tele2. I have firmware 2.2 and baseband 02.28.00 (100% sure). One odd thing I've noticed though:

When I run the yellowsn0w command in Mobileterminal or through SSH on my Mac, the output is:
open: Resource busy

I get that output whatever command I utilize! yellowsn0w -a = open: Resource busy. yellowsn0w -q = open: Resource busy :S