Chodon, we live without TV (intentionally...I know, we're freaks), so i haven't yet caught the "Life After People" show. I did hear about it, though, and hope to catch it on one of our TV nights with friends (Sunday night was a documentary on Giant Squid!). It sounds heavily based on the book, and Weissman is not shy about letting folks use his material: Scientific American published about 15 pages of the book several months ago in an issue pretty much dedicated to his work.
The "20 years after" tour of Chernobyl is something I definitely want to catch! So far, I am really loving the book. Weissman's a font of weird and (usually) interesting facts, some of which take a while to make their relevance to the topic at hand known; and, that is the kind of thing I like. Sounds like the show has some of that, too. Can't wait to see it!