So How will this work then? Ok I have two phones now the n900 and nokia e71, now I hvae 1 sim card of tmobile with a phone number for alot of years now, and this phone number is important because I hvae my own computer tech businness here in california so all my customers that call me I need whatever phone i have to be able to reach me. So what tricks/steps I can do to sometimes depending ont he day and such when I want to carry one phone at a time without switching sim card to be reacheable when custoemrs call me. Thanks