If you want it to do serious road work, then:
1: I'll reiterate slicks. I like the
Bontrager Road Warriors a lot.
2: Change the fork out for a lightweight rigid one. You've probably got an extra two pounds on that fork.
3: A complex solution: You may find that you can't get in a high enough gear. If that's the case, I'd hunt around for a used road chainwheel/crank in the 48-52 tooth range. That may make it so your front derailleur no longer really works (you'll at least have to move it up the frame), so you might need a new front derailleur. Fortunately, front derailleurs are really cheap (~$10 on Ebay all the time).