IP address?!?!

Hi, I was just wondering if anyone could help with my problem?! My wireless internet is connected to my internet provider, so the wireless box is full, however on network diagnostics it says:

"Airport does not have an IP address and cannot connect to the internet"

I was just wondering what is wrong with my macbook, everything else is working fine.

Thanks!

We need some more details. DSL or cable Internet or something else? AirPort Express or Extreme? If your MacBook is connected to your AirPort, but your AirPort is not connected to your ISP you are not going to get very far. When I say connected, I mean more than just physically connected...

Are you in range of a wireless network? If so is it secured and is it yours? after that if YES then can you access the router? ....