YouTube is blocked live for me, since the first race day. It says it's blocked in the US, but it may be regional. I haven't been able to see the races on youTube until 6 hrs later. If I go straight there over coffee in the morning, I have often seen the race before I hear the result.
If I happen to be able to catch them live, the NBC Sports iPad/iPhone app has worked well. It's free, but you must sigh up via your cable TV account. You don't pay your cable carrier, you just need to have already paid for the service indirectly.
While not live, it's nice to catch them on Youtube without commercials.
I got this from CF:
You can stream it via a proxy server from another country.
The easiest way to do that is to use Firefox with the Hola unblocker plug-in (Hola is also available for Windows Internet Explorer, Android, Chrome and other browsers) it's also free.
Hola puts a little flamming smiley in your toolbar. Open the AC feed on YouTube, if it shows 'blocked' just click the Hola smiley and choose another country to proxy from. Bada Boom, Badda Bing ... AC racing on your monitor sans cable fees. You gotta love hackers.