The chief disadvantages of o9 are

1. no voicemail provisions

2. no coverage in Switzerland.

3. No text messaging.

UM, as noted, has worked very well for incoming for me throughout all of Europe. Callbackworld has worked pretty well but has sporadically had problems. Using United Mobile to call the USA without callbackworld is expensive but less so than most roaning situations that exist today. Biggest problem with UM is the incoming calls on most long distance carriers in the USA are asininely high (you have to check out rates to Liechtenstein mobiles) with the exception being the $1/month AT&T plan noted above (but as with all these rates, I suppose if too many people find out they will raise the rates as so many of the US ld carriers have done to rates to Liechtenstein mobiles with the final culmination being the 100% increases in rates using callbackworld which occurred a scant three weeks ago).

On this site, you can read up in the operators sections on the various international sims and by going to the web sites, you can check out incoming rates to the various countries you will be going through. The international sims use mobile phone numbers in Liechtenstein (United Mobile), Iceland (o9), the Isle of Man (which is really a UK number and some of the voip operators have very good rates to them) and Estonia. Also I do agree that vodafone passport might be a suggestion but getting it started and up and running from the USA might be a problem.

And as noted, if the eu communications people have their way, it might be (but don't hold your breath for this summer) that sooner or later roaming in Europe on any carrier will be the same as roaming is in the USA.

Ultimately, as noted, the sites to check out for rates are www.callbackworld.com, www.voicestick.com and www.kall8.com. All can give you reasonably cheap US numbers to reach various European sims but rates can vary by country of the sim.

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.

T-Mobile has that? I haven't seen one of those. However, look at the international SIM section on this site. It sort of depends if you want to pay the tab for the in-laws calls or you want them to pay the tab. There are several cards that feature "free incoming" calls in most of Europe.

I was going to suggest Yackie since they give you a US number, so I went to their site to check the rates for those countries, and here is what I found posted in the news section. So, yackie may not be an option at this time.

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Dear Yackie Mobile Customers; Do to some changes we are in the process of making, to advance our technology toward the future of GSM telecommunication; all Yackie Mobile services are temporally suspended. We apologize for any inconvenience; we will provide you with alternative services until we have completed our upgrades to our system.

I've pretty much written Yackie off. They just do not seem reliable.