The long standing tradition is that there are no attacks on the Yellow Jersey on the final day, which is essentially a victory parade. There will be a sprint finish as the sprint champion (the green jersey) is to be decided.
The race seems confusing, but it really isn't. The Yellow Jersey (The Maillot Jaune) is awarded to the rider who completes the entire course in the shortest elapsed time. It's possible to win the "overall" or "general classification" without ever winning an individual stage. However, it is thought that to win "properly", a rider must win at least one stage, as Landis most convincingly did.
The other jerseys, the green sprinter's jersey, the polka-dot "king of the mountains" jersey, and a couple of others, are awarded according to a complex point system involving placing well in on-the-course "field sprints" and of course, the final sprint to the finish during the flat stages.
There is a white jersey awarded to the most promising young rider as well.