All you need is a PC with a TV tuner, and Yahoo's new Go for TV service. The service built on a Meedio backbone (which Yahoo recently acquired), is available for free via download.
Most PC's that come equipped with a TV tuner, generally have software included to exploit the feature, but users tend to find them limited in their capabilities. The Go for TV service will certainly provide some competition for other DVR software such as Windows XP Media Center Edition and content providers such as TIVO or other DVR devices which will have you shelling out some major mulah, vs the reasonably cheap cost of adding a TV tuner to your pc & Yahoo's new service.
Now you can watch TV how you want to...on your pc.
In addition to the DVR features Yahoo has incorporated the ability to manage your music and video and pictures as well as giving you features like movie previews. Check it out.