Search online, I've heard that there are variations where any type of grains or beans aren't allowed. Then there is also the rules of kosher where a meal may either have meat OR dairy but not both. I would basically try to keep it simple
This looks like a good recipe: (Cabbage salad)
http://recipes.holidays.net/view_recipe.php?id=287
Here is a list of lots of recipes:
http://www.holidays.net/passover/recipes.htm
I wouldn't try to cook a 'traditional' item though but something that stays within the guidelines. A nice fruit salad seems like a good option too.
(Disclaimer - Not Jewish, never been to passover dinner but did have a few good friends that were Jewish in college and spent quite a few dinners at parents of one of my friends)