Unless you do something today, there will not be a Third Season. Call your local FOX affiliate station and ask them to lobby the FOX network for the SCC's return to the Summer and Fall schedules.

http://www.squidoo.com/The-Sarah-Connor-Chronicles

I'm a little late in answering this question and by now i'm sure you know the answer to the last part of your question. Yes the show was cancelled. But heres what i think, i loved the ending of the second season. The cliffhanger was amazing. When he turns around and see's his dad for the first time in his life, i thought that was great. They could have done so much with that for a third season. And although some people say to never lose hope, it still destroys me that i will never get to see how the rest of that scene would have gone.I really hope that the show gets picked up again but i doubt it will. Like with most things that are great they killed it.