It's basically the same as "What's up?" or "What's happening?" So it is usually used informally between friends as a greeting or right after a greeting.

Hi Mina, you can listen to a song called "Hey good looking, whatcha got cooking?' here http://www.youtube.com/watch?v=NWZ0BuHJ4Eg

Basically, it means what's up. But "is cooking" is a present continue tense. It is asking what are you doing now. "What's cooking" is colloquial English, the listeners may have slight different meanings to them, it depends on the situation, when and where you say it.

Hi... "What's up" means "what is up to..." = "What's new?"

What's up