Well first off what you're looking at is making a swerve drive robot. They are complicated, often require a lot of machining and good coding. I'm going to recommend that you don't just try to do this on a whim. My team back in 2002 thought we could just make a swerve drive in 6 weeks and it ended with a robot that couldn't drive at all. I'm going to recommend that you try putting this on the back burner and do it as an off season project.
That being said, if you want to go ahead the more power to you, but don't say I didnt' warn you. A good place to start is with a CD-media search of swerve drives. Hopefully this link will work
http://www.chiefdelphi.com/media/search/results/28297
If not just do a search for "swerve" and you'll come up with pages and pages of pictures to start with.
I don't know of a good source of swerve drive drawings, but hopefully a team that has built one succesfully(my team has yet to
) will offer their services. Things to look into are using the Nothing but dewalt gearboxes to provide a nice gearbox for each wheel, I think HOT made a set up like that.
Other than that Good Luck
(and please have a back up plan
)