(gsm) see http://talk.maemo.org/showpost.php?p...&postcount=104
It seems under certain circumstances (re PIN) the modem can handle swapping the SIM, and you can make maemo side software to handle it as well, by e.g killall csd. There are still several problems like operator name shown etc. Check out peterlienchen's simswitcher app for how to handle all that, you might patch it for your purpose

ps: thanks for 4444 thanks to whomever it been, I owe you a schnaps
/j