as far as I know, you basically use the same method as when you create a http link, but instead of putting http you write 'tel'. Have a search in the forum, the same question has been asked a few times.
unfortunately, nothing. the sdk doesn't expose the functionality that you seem to need. the tel: url, as suggested above, will only launch the phone application on a (real) iphone, and at that point your application will forcefully terminate.
my plan was canceled. I'm interested in the functions relate with phone features. I studied to create a program like a part of iBlackList but it's too difficult.
You can see iBlackList at http://www.iblacklist.com.br/