This week's book giveaway is in the Java in General forum. We're giving away four copies of Java by Comparison (eBook) and have Simon Harrer, Jörg Lenhard, Linus Dietz on-line! See this thread for details.
What device and what carrier are you asking about?
You can make a text field that give the user an option for dialing, but there's no standard method for forcing a phone to dial a number from a MIDP 1.0 application. Often there are custom extensions to do the job. Here's an example: