How about other useful sites, like:
http://www.Zap2It.com - select program listings and enter zip code of the person you're trading with (I use 90210 for LA, and 19446 for Philly)
http://www.Dishnetwork.com - select programming guides and Eastern, Central or Western time zones
http://www.theFutonCritic.com - often have up to the minute news on schedule changes that not even Tivo or DISH's online guide picks up on, as well as reviews, announcements, and tons of information
http://www.RadioTimes.com - UK television listings, searchable by title only
http://www.digiguide.co.uk - UK television listings, searchable by anything. Has a desktop version with a free month's trial, and an inexpensive annual subscription fee
http://www.SFTV.org - SF and fantasy in the US, often forecast a month or so in the future, with titles, production numbers, and airdates
For cable networks, there are:
http://www.sho.com - Showtime, including all its subsidiary networks
http://www.hbo.com - HBO
http://www.scifi.com - SciFi Channel (there's a UK site as well)
I have a whole bunch of useful web sites I've collected that help me find out what's coming on in various places - I'll add more this evening. I haven't found a good resource yet for Canadian television listings, so I'd love to see someone add that. Ditto Australia.