If I may off one piece of advice that I learned the hard way.
When playing in your Custom Settings for auto focus, never select "Dynamic Area"

As a newby with the d80 and using "The Digitutor" I had determined Dynamic Area focus was a good place for a beginner to start since it allows the camera to determine what to focus on.
What I ended up with was hundreds of pictures that were back focused.

Only with some help from this site did I get the problem diagnosed and resolved.
If you'd like to see some examples of this problems here is the link to my focus issue.

d80 owners that upgraded to d90's ???