http://wtng.info/ http://wtng.info/ would be a good place to start. It's a lot of work to do right. You have to support full international numbers as short as

http://wtng.info/ http://wtng.info/ would be a good place to start. It's a lot of work to do right. You have to support full international numbers as short as 7 digits (Tokelau has +690 XXXX) and as long as 15 digits (in Germany the telco basically gives subscribers a subnet-like functionality, as extra dialled digits are passed along during call origination). Ideally you'd be able to parse it into a punctuation format based on local practice, but just about everyone punts on that.