David Pogue, technology columnist for the New York Times, and basically a very knowledgeable and reasonable writer on the ins and outs of technology, has written a column on the newer features of TiVos. He covers most of the networking features of standalone Series 2 and later units. It’s a pretty good overview of what’s going on:
The article is here.
Whoops – didn’t catch this the first time. The basic info from the article is also contained in this video.