Had an idea for an Android app, and I suppose it could be ported to iPhone, but it's not something I'm as familiar with.
There are tools like
http://www.recipematcher.com/ which take input on what you have in your pantry, and help you build a menu off it.
The problem is sitting down and typing in everything into the webpage, or whatever.
There are also tools like ShopSavvy which can look up the item based off a picture of the barcode.
Combining the two things together would be awesome.
You could take pictures of the stuff in your pantry, feed it into the recipe tool, and it would spit out what all you can make.
Certainly some things you would need to be input manually (bulk meat comes to mind) but it would simplify things greatly. Taking it a step further, if you marked the recipe "made" it could remove the items from its records, and as you grocery shop, you could scan things in again. Need an idea for dinner? tap a button on your phone.
I have looked around, and haven't seen anything like it. The biggest challenge to me is that I'm really not a programmer. I worry that anything I could put together would look like crap