You guys make better pokemon and games then satoshi, gamefreak and nintendo put together.
Even though that probably wasn't directed to me in any way, on behalf of this forum as its mod, thank you ;)
As far as I know (correct me if I'm wrong, anyone), there isn't a tool specifically for making pkmn games. Last I heard, though, ashly138 had plans of making one in VisualBasic. I don't think he's actually started working on it though.
Most of us use RM2K (hence the forum title). Read the FAQ for further details. It's probably the easiest program in general, but making pkmn games can be challenging. Fortunately for you, however, most of us in this forum are competent enough to answer any of the questions you may have and offer help.
The rest of the people use other programs such as Sphere and GameMaker. Game Maker is best for Pac-Man-like games, and Sphere allows you to script everything in JavaScript. Sphere is the most challenging because you have to program everything, but Sphere games can sometimes be better.
It's all up to you :)