[Bossman]

You have already received excellent information from the very knowledegable folks here.

I just want to add that, since it seems like ease of your family getting to you is very important, you may want to get a free US number from voicestick.com, and just forward it to whatever international/foreign sim you go with. The only cost to you will be the forwarding cost. For example to forward voicestick to UM it's $0.30 I think, and it's $0.16 to a vodafone UK number. Check their website for more info.