Citibank has offered Virtual Numbers for about a year. They have software that once installed on your computer, will automatically generate a number and expiration date and rear card code and even fill in credit card info on web sites. Your son probably could open an account over the telephone or on their web site.

The numbers don't seem to work when the actual charge date is over a few months into the future.

I use my virtual numbers all the time and feel very secure with it's usage.

I would be very wary of sending a credit card number to anyone I didn't know in Rio and I definitely wouldn't give them the rear panel code.

Peter in the Bay Area