How can I transfer a live television show to my computer?

For example, there is a show going on, on my cable television. I want to view and record that show on my computer.

-What devices may I need?

-What softwares may I need?

-Is it even possible?

-Do I have any other alternatives?

I have a DVD writer, so if that plays a part in direct recording, let me know.

A TV Tuner Adapter

SageTV software

or maybe even Roxio Media Creator Suite 9

www.roxio.com

Dazzle sells so items that can do this for you with software included.