Here are some of the website that I often get to watch games from GSL,NASL, etc and I am sharing with everyone here.

Global Starcraft League(GSL)

This is the largest starcraft 2 tournament to date held in Korea featuring the best Korean pro gamers.

1) www.gomtv.net
This is the official website for GSL and you can watch it live but in lower resolution modes. In case you miss out the live actions, you can check out some of them in the video sections.

2) StarCraft 2 Replays | SC2Rep.com | Spawn More Replays.
You can catch all the GSL games and other major tournament games here, great site.

North American Star League(NASL)
This is the biggest league in NA.

1) www.nasl.tv

First Person View Streaming
Team Liquid - StarCraft 2 and Brood War Pro Gaming NewsTeam Liquid - StarCraft 2 and Brood War Pro Gaming News
A very good website featuring a lot of pro gamers doing live stream.

Hope this helps for all Starcraft 2 fans here. Cheers