I'm not so sure you'll find something on the Internet. Having the codes to program keyless entry just floating around might negate the security of keyless entry. You'll probably need to call a Pontiac dealership. It doesn't hurt to just call one and ask too.
You might have luck going to a public library and looking in the auto manuals section. The library where I grew up had repair manuals and wiring schematics for pretty much every domestic car from the 1950's onward. You might be surprised at what you find.
Motortopian. Lover. Code Geek.