Yeah a new key switch will likely solve the problem. You will have to tear down the column to replace it. BuddyCraigg has a good step-by-step process video on YouTube (you'll have to search for it) to replacing the key lock cylinder assembly, and you can also find Jazzman's steering column assembly guide here
(for you, you would read the guide backwards). You can buy a whole new cylinder assembly with keys.
If that doesn't solve it, then likely the sector gear is jammed or something else is holding the lock cylinder in place. You'll have to tear the column further down to replace what is likely the sector gear and actuator throw arm, and if you have tilt it requires removal of the entire column to remove the tilt pins. I don't think this is your problem though, as if it is an actuator arm jam you would know it because you would have broken the arm trying to turn the key (they're very fragile when forced).
[This message has been edited by Fiero84Freak (edited 07-08-2013).]