Since I moved recently, I went with a Vonage phone that works with my cable modem instead of opting for a standard landline from the local teleco. I knew going in that Vonage clearly states: "We do not currently support DirecTV and TiVo."
So instead, I checked around the TiVo Community and noticed a lot of people happy with their Linksys wusb11 wireless adapter. The problem I found tonight is one of the first steps in the guided setup requires a call to TiVo. All the TiVo docs about getting your machine on a LAN present screens from a fully functioning Tivo, and there didn't seem to be a way around it in the setup.
I decided to call customer service and get the secret backdoor to skipping the call. The customer service phone number listed on the TiVo site has turned into what my friend Merlin dubs "phone jail". You can't hit buttons, skip to a live person, or otherwise get around a slow talking robot that requires you to speak in order to issue commands. Eventually when the robot couldn't help me they gave out the real customer service number: (505) 348-2800. After talking to a human it was revealed that you can't setup a brand-new tivo without a landline. The reason he said, was that TiVo doesn't ship all new units with the 4.0 OS, and without it, LAN connectivity doesn't function. He said that hopefully in the next six months, setups without phonelines would be possible, but currently it was not.