First of all, you'll need either a flash linker or a decent emulator to test your programs. There are still a few companies selling flash linkers but they're getting harder to find
Secondly; visit these sites:
<a href="http://www.devrs.com/ngp/" target="_blank">http://www.devrs.com/ngp/</a> - General NGP development portal
<a href="http://www.btinternet.com/~rog666/help.htm" target="_blank">http://www.btinternet.com/~rog666/help.htm</a> - guides to installing and compiling using both Assembler & C (includes full downloads)
<a href="http://www.severnroad.co.uk/ngp/" target="_blank">http://www.severnroad.co.uk/ngp/</a> - The C Framework - essential set of library functions for tile, sprite, sound and all sort of other goodness
<a href="http://www.ahchay.com/ngpcdev/tutorial.htm" target="_blank">http://www.ahchay.com/ngpcdev/tutorial.htm</a> - A tutorial to guide you through creating a (very basic) game using the C Framework.
Thirdly; join the NGPCDev mailing list at <a href="http://groups.yahoo.com/group/ngpcdev" target="_blank">http://groups.yahoo.com/group/ngpcdev</a>
Good luck! Post a follow up, or feel free to email me, if you want more specific advice
Cheers
Chris