I am just finishing up a trip to Shanghai China, Osaka, and Tokyo. I brought a MagicJack phone adapter.
This gave me a US local number that rang to my computer or what ever computer I plugged it into. The voice qualify was great and it worked flawlessly on both a Mac and PC.
One really nice feature was that I could plug the USB key into any computer and I had a free telephone to use.
It costs $39 for the first year and $19 for each year after that. No long distance charges or monthly charges.
I think anyone who travels should have one of these. If you would like to try it out, Contact me and I would be happy to call you or have you call me on it.