I have used http://www.gototaltrainer.com and it is really good. Not only do the meal plans they come up with perfectly within whatever constraints you set, you can also typically find recipes that are actually are enjoyable. It just seems like they have a pretty big database and a good algorithm to figure out the meal plan.
That site needs some serious work - I spent a couple minutes trying to figure out how to use it or get it to do anything before figuring out I had to contact them to try it out. No thanks.
