Laptop connect usb modem for Ubuntu???

I installed ubuntu (10.04 LTS) on a Dell 1525 and got the wireless working on my local wireless network and also on the ethernet cable from my router. I have not been able to get the laptop connect card from AT&T (Mercury–AKA Sierra) to connect to the internet. Any suggestions would be appreciated.

Have you read this website?

I have now!!! Thanks!!!