Probably the best thing is Orb. Orb itself is free, but the catch is you need a TV Tuner set up on on a Media Center PC at home (recommended, but it can be used on standard XP also and of course Vista.) You create a free account and access is entirely web-based. They have a special mobile version of the home page too. Not only can you watch your own live TV but also your recordings, your music collection, and viewing your photos.
www.orb.com