Painting Wood Desk

[calusa.livejournal.com]

I have a desk, which I imagine is pressureboard covered in that stuff that makes it appear to be real wood. I picked it up at a Salvation Army store for like 5 bucks, so it's not exactly the cutest thing in my room; but I want to dress it up a bit.

My idea is to cover it in a base coat of paint, and then use acryllics or something to paint an underwater scene, and then cover it with a protective coat.

1) What should I do to prepare the fake wood for painting?
2) What should I use to cover the finished project?