It will work. Most plasmas will have the needed component hook-ups to allow Tivo to play back. I assume that you have the series II tivo. Keep in mind that with a plasma, "old-fashioned cable TV" and a series II tivo, you won't be able to record and play-back any hi-definition broadcasts. You will need to upgrade to digital cable (with the HD service) and get an HD compatible Tivo box. If you don't want to do that, the series II will record and playback shows just like before. Just make sure that the plasma you buy has the needed connections.

Just my .02, unless you can get OTA HD signals, buying a plasma with out the HD service is like buying a car and not being able to drive it. If you get a HD compatible set, figure out how you'll get the HD broadcasts either OTA or a service (cable, etc)

Their Series 3 is the HD unit. Records up to 300 hours SD and up to 32 hours HD and I believe it works only with cable. Also runs about $800 on the TIVO web site.
And I agree with sacto diane about buying the plasma TV and no HD service. Plus, from what I've heard, SD on some HD sets may not look very good.