There are plenty of tools available in the Market for Mobile application and game development. Which one is your choice?
I found few articles, which gives a list of tools for Windows mobile as well as Java (enabled) phones – I mean Windows CE.NET and Java ME (J2ME).
Michael Juntao Yuan of Java World.com has written an extensive article on Java Mobile development tools..
For Windows mobile development, Microsoft offers many tools and kits. Click here to see them.
I personally recommend the following few:
For Windows Mobile:
Visual Studio 2005
Windows Mobile Developer Resource Kit
Here is a page of resource, which gives you details for all the technologies including Appforge and Codewarrier.