What do you need to make an amv?

Depends on what type of system you've got.

If you've got Windows, there's Windows Movie Maker for free. It's simple to use and the it keeps the most of the quality of pictures but it tends to changes the colour.

I don't know any MAC programs though.

You can also download Sony Vegas Pro which has alot of features and makes fancy good quality videos. Can't say it will be easy to use though.