So I am using AT&T Uverse via the provided 2Wire 3600HGV router. I was able to connect to the wireless connection when I was using the live cd and installing Ubuntu, but after the install and restart I could no longer connect. Every few minutes I am asked for the network key, but it never finishes connecting
Does it work with Windows? Or is this specific to Ubuntu?
Can you get to the Uverse router management page? The default URL is http://192.168.1.254/ . I would check that page out, and make sure that your system is showing-up there.
How many other devices do you have on the Uverse WiFi? If I remember right, AT&T Uverse allows a maximum of four devices. Make sure that you're not violating that limit. Can those other devices connect properly?
I actually got around that limit by using a router as one of my devices. That way, my five hardwired computers would register to Uverse (through the router) as one device, and my laptop, Wii, and my wife's phone could take the other slots without worry.
But I don't recall anything specific that I had to do to get it to work with Ubuntu. Anyway look into some of what I've posted above, and see if it helps you.