Test Match Special, which is streamed live on the website with no lock-down to international users like me, at least for the home tests like this.
But what about watching the Test Matches if you are in America? There are two legal ways to do this. One is to get satellite TV. Direct TV have cornered the market here, but I think you can get hold of cricket on Dish too. This is not an option for us after the trauma of trying to get satellite installed in order to watch the cricket four years ago, a story detailed on The Americanization of Emily.
The second legal option is the one that I go for: Willow TV. It's pretty good and it is getting better all the time. This year it is $150 for all international cricket for the entire year, test matches, one dayers, Twenty20, in all countries. This is far, far cheaper than the equivalent satellite price, either here or back in England. It streams at a reasonable quality, similar, say, to watching the BBC iPlayer live. If you have a good internet connection and router, it will stream without interruption. They have a choice of different feeds and the one I always go for is the feed that comes directly from Sky, which enables you to watch in wide screen when you plug the laptop into the TV, and which retains all the Sky adverts, which gives the Resident Alien a great taste of home.
One thing I like about Willow is that it is just username and password based, so you can watch on any computer you like, at home or at work (shh!), as long as you don't do anything daft like trying to watch it on two machines at once. The only disadvantage is that the live feed has a delay of about 15-20 seconds, so you can't really watch it with the sound down while listening to TMS, unless, of course, you would like to hear the commentary first so that you know to pay special attention to the pictures when something really exciting happens.
I should add that I am not on commission here, but mention it because a lot of people do not realize that Willow TV provides such a good solution for the cricket lover out here. I only discovered it by accident back in 2006.