On any bike that's been sitting for years, you'll want new rubber. That's tires & tubes. Gear and brake-cables replaced, and new cable-housing as well. And a thorough cleaning and lubricating.

Here are two sites that can help you increase your knowledge about how bikes work and doing repairs/tune-ups yourself:

http://www.parktool.com/repair/

http://bicycletutor.com/

And a word or 1,000 from the Master Himself:

http://sheldonbrown.com/harris/#articles

Happy Trails!