Awhile back Smith-Micro introduced DTV4PC, and it still has a heavy e-mail spam strategy that promises to turn PCs into complete entertainment centers. As Vodyo (a blog about online TV) explained last year, the DTV4PC is $30 software that aggregates Free To Air (FTA) channels and packages access with a custom user interface and search function.
What's interesting is that FTA channels are already free to anyone with an internet connection or satellite dish. There's even a website that aggregates the online versions of these channels: World Wide Internet TV, wwiTV.com. It's a great way to check out marginal television from all over the world -- here's something from Europe for weathercasters who are bored with props like rubber duckies and umbrellas:
Something similar to wwiTV programming but just from the USA is AmericaFree.tv, which uses QuickTime streaming. And though everyone knows the best ones already, more options for both free and pay models are listed at the dateless and aged Daily IPTV articles A TV Guide For IPTV: 100 of the Best Internet TV Channels and IPTV Startups to Watch.