Visual basic is what alot of things are built in.
or .net (which can be slow, well atleast definitely slower than visual basic)
If you want .net,
here's some sites to check out:
8 links to must know .net sites:
http://www.makeuseof.com/tag/8-web-s...ld-know-about/
another one I use for some things:
http://buzzdev.net/index.php
Also, google will help you find tons of other .net information.
Also, I recommend getting the device emulator from microsoft.com
Also, check out the msdn.com for a bunch of info from microsoft on programming.
Tons of info there.
also, here's a wm6.5 developing kit from microsoft itself.