The basic question is: Can you draw?
There'a few ways you can start, but the most fundamental is learning to draw people. I'd take a couple of life drawing classes, or just attend an open life drawing session (they're usually cheap and you bring your own paper) to get an idea of how people work. Everything from weight to gesture is important to learn, and it can take a little while.
If you can already draw fairly well and just want to learn how to make panels flow, how dialogue works, and so on, there are any number of tutorials out there, and I would advise taking a night course on that kind of thing. Art colleges tend to offer that kind of independent course.
I like this one as a tip for general purposes: http://joeljohnson.com/archives/2006/08/wally_woods_22.html