clipped from: www.lifehacker.com 
Ever since TiVo came around, I was eager to jump on the time shifting bandwagon. After all, nothing makes a productivity junkie happier than turning an hour-long show into forty minutes. But for all its loyal fan base, TiVo never seemed like the right fit for me.
First things first. If you’re going turn your TV into a DVR, you need a capture card. A capture card is a USB or PCI device that you install on your computer that allows you to plug your TV cable into your computer the same way you would your TV.
Although MythTV is probably the most powerful of these programs (and it’s free), when all was said and done I chose SageTV for its feature set, stability, and Windows/Linux support. Aside from its very active support forums, you can also get support directly from a real company, which is always a nice option. Out of the box, SageTV installs as easily as any Windows program, and configuring your capture card with SageTV is a breeze.
Customize your SageTV: If you’re not happy with the default UI of SageTV, there are some beautiful user-designed packages that are easy to install. The best one I’ve found is called SageMC16x9.