How do pencil and paper RPG's work?

[2012 Wont Happen]

Me and my friends love RPG video games. We've also recently all become huge fans of Unforgotten Realms. Due to obvious combination of these things, we're thinking about trying some old-school p&p RPG's. Unfortunately, we don't know how they work... at all.

To keep this easy I'll ask about the most popular one (to my knowledge)

How do you play Dungeons and Dragons?

any is actually fine, just for specificity's sake I put that

 

[MasterSqueak]

Um, there's a Play-by-Post DnD game going on currently. Ask Ninjablu, he's the GM.