Alas, the time has come for me to air my ignorance:
I am a relative newcomer to linux and am currently running SuSe 9.3. Until recently I could only access the internet via a dial-up connection, but am now able to use broadband ADSL at 512k.
I had no problems configuring my modem for dial-up, but I have not yet been able to configure my D-Link G604T ADSL router to allow access from my linux system to the internet.
I am able to access the router from Linux as address 192.168.1.1 to enable me to set it up, so I know that the router is somehow connected. I am also able to access the internet via this router from, dare I mention it, Win XP, but for Linux the secret eludes me. I have spent a couple of weeks trying to find the answers from various sources.
Ironically, one of the reasons for me moving to linux was that there is too much hand-holding in Windows, so I find this rather embarassing.
Why don't you try this script !!