Really? How? And what else can I watch? Movies?
TV episodes from lots of different cable and network companies.
Check out Apple iTunes' Music Store. You need to download iTunes and install it on either Windows or Mac. Check the Apple web site for the program.
If you get a video enabled iPod, you can even take your favorite tv programs on the road with you.
The episodes are commercial free, and I think the new episodes are posted for purchase and download within 48 hours of their airing on cable or television. I could be wrong about the latency, it could be shorter.
Eventually someone will tell you that there are less legal ways to obtain the episodes, but I've found that iTunes is more reliable and usually faster than searching for episodes of my favorite shows on the file sharing networks.
The quality of the iTunes episodes is pretty poor. They're designed to be shown on a video iPod, so they are shown in a really tiny window. You can blow it up, but you really lose detail that way. Plus, the iTunes version is typically pan-and-scan. I know all of this, because I recently bought the fifth season of Alias through iTunes. It was watchable, but only just. Of course, it's cheaper than the DVDs. But, if you want it to watch on your TV, the best bet is to either NetFlix the series, or buy the Monk: The Obsessive Compulsive box set. It collects seasons one through four in a discounted single package.