I dont have cable and last year I wanted to get MLB.tv but I found out that since my IP address was from Massachusetts all of the Red Sox games were blacked out.
I had a DD-WRT router where I connected part of my network to a VPN service like this one: http://www.hidemyass.com/vpn/
Then I used AppleTV to watch MLB. I only had part of my network connected to the VPN because the Internet download speeds through the VPN were only 1-3 mbps if I remember right. A much simpler setup is to just connect to a VPN through your computer and watch MBL through your web browser.