Wireless intranets FAILED!

Okay, 4chan, here's the deal.
I have a wireless network set up and my laptop connects to it just fine, but then it won't let me on the internet.
It tells me it's connected and it's both recieving and sending packets, but when I boot up my browser, or try to connect to AIM...FAILURE.
Anyone have any idea why this is happening and what I can do to fix it?
My brother has the same problem.

OP here, I mean that my brother also has this problem with his laptop, it's the same network.

Good things to check, in order of easiest to hardest:

Is the wireless router hooked up to the internet?
Can the two computers talk to each other?
Do you have the proper drivers for the wireless hardware?
Is your router set up correctly?

Do your computers know about your router's internal IP address (e.g 192.168.0.1)?

If you have some wired ports, do they work?