@MrsPramm - You don't need to take a class. Just download a computer graphics program and start practicing. You don't even need to spend money on the program. There are plenty of free ones around that are more than enough for a casual user and I know lots of people who use them for professional work as well.
Figure out what kind of graphics you want to play with (do you want to make vectors, or work with pencil sketches, or what?) and go through the tutorials they have online for a program that handles that kind of art. Once you've got a grip on the basics, it's just a matter of experimenting and practicing. There are lots of forums dedicated to helping people with this kind of thing.
People think of art as some kind of mystical ability, but, for the most part, it's just practicing. If you can make a pencil go where you intend it to go, there's no reason you can't create something beautiful.