How to find out your number on AT&T?

I brought a phone in england on the 3 network. i am on holiday in the U.S.A and it changed to AT%26amp;T but i do not no what the number is so people can contact me. is there a number i can dial to find this out ? all help appreciated :)How to find out your number on AT%26amp;T?Either call someone who has the caller ID service or contact AT%26amp;T customer service for assistance.