How to watch cable TV through Ubuntu?

Is it possible to watch cable TV (specifically Comcast in Massachusetts) through the monitor of a computer running Ubuntu? If so, what additional hardware and software are required for this? Better yet, is there a step-by-step how-to for something like this?

You will also need some software. I like MythTV, and it has a list of digital tuners that work with MythTV.

There are also analog tuners, but you will probably need a digital tuner unless you have a digital to analog converter box. The signal may be encrypted, so you may need to use the box and get an analog tuner.

Here is a page with links to different supported cards.

I know nothing about ubuntu but the hardware you need is called a TV tuner card. Actually I think they make external ones too. Make sure it accepts the cable input (coax or whatever). The software will then allow you to watch TV in a window and you can continue working with the OS. You can also record. I found this via google, maybe this app is the right one to use with your hardware: http://ubuntuforums.org/showthread.php?t=230279