I wouldn't even bother with serial numbers. Every good Pocket PC game and application that has ever came out has been cracked. Your application will be warezed no matter what you do. Even the most complicated registration programs like Dan East's Dexplor or Eidos's Tomb Raider have been cracked. Their are some very good crackers who work for the groups PDAwarez, CorePDA, and Nirv (A.K.A. PocketWarez). You can still try, I suppose. At least it will keep your product from being pirated for a little while. Sorry.

We all wish we could do something about the warez problem, but so far nobody has come up with anything.