Since no mention of the cable modem I can't tell if you forgot to power cycle the modem or not.
That is, this post is "light."
Trying to setup a Linksys WRT 54G Router ver2. it's install right all cables are on right the setup page come up all setting look ok, but no internet???? all computers on this home network are running ubuntu 9.04 and all work fine with other Routers. only the Linksys has no internet.