If you really feel the need to create but lack the artistic clout to get very far, you could always try collage style re-use of existing images or clipart, (see things like Qwantz, or DM of the Rings/Darths and Droids.

If nothing else, it could serve as some kind of proof of concept, allow you to rough out some simple ideas to show people the kind of stuff you have in mind storywise.

It'll be a lot easier for artists to step forward and commit themselves once they have an idea of what your writing is like I'd guess.