Here is the solution !!! Check this link or read answer below from same link !!!
Answer from LINK:
Just to expand on an earlier answer, something like this does it for me:
NSString *num = [[NSUserDefaults standardUserDefaults] stringForKey:@"SBFormattedPhoneNumber"];
Note: This retrieves the "Phone number" that was entered during the iPhone's iTunes activation and can be null or an incorrect value. It's NOT read from the SIM card.
At least that does in 2.1. There are a couple of other interesting keys in NSUserDefaults that may also not last. (This is in my app which uses a UIWebView)
WebKitJavaScriptCanOpenWindowsAutomatically
NSInterfaceStyle
TVOutStatus
WebKitDeveloperExtrasEnabledPreferenceKey
and so on.
Not sure what, if anything, the others do.