Where is the phone number stored on the SmartPhone?

We've been looking into this issue lately and there are a number of solutions floating around the web. A colleague of mine in the lab has even written a utility to dump SIM storage memory and look for the mobile phone's number. Of course, you could always use the SmsGetPhoneNumber API in the SmartPhone SDK but that's not always guaranteed to work either.

From Hung Dang at Microsoft,

You can query the phone number from the device with the SmsGetPhoneNumber API (see Smartphone 2003 SDK). Note that not all SIM's contain the phone number, so you cannot always get the phone number.

Google Groups link.