Me and a couple of buddies started thinking about making a really simple RPG.

I mean simple. The ideas have been thrown around, but we're not too sure where to even start. My friends have gone out of town for the weekend, and I wanted to start on some of the classes that will be needed. Without getting into the actual game MECHANICS or display, is there anything that I could start up on?

We were thinking of having things VERY generic. I mean (eventually, when we get to using graphics), generic enough to use it in a DND style setting, or in a StarWars style setting.

So with all this in mind, is there something that I could start on???

We also want to put everything into classes. Like have a player class, a monster class, weapons class, etc...

Look into Q-Hack, Net-Hack, or any other popular open-source RPG (maybe you could find more on SF.net). And a good general overview of engine design (though maybe not quite what you are looking for) can be found in Teach Yourself Game Programming in 24 Hours published by Sams, you can find it at many library systems.