US Carrier for Prepaid + Roaming in Europe?

[rfranzq]

Truphone allows porting a number. I am not sure how easy it is to do and I don't know if it comes close to your needs. SMS is free to receive everywhere. Voicemail is available.

Does anyone else know of any international SIMs with the ability to port an american number to it?

Keeping an Existing Mobile Number
If you would like to transfer your existing mobile number to Truphone contact our Customer Support team.