I found an interview for Absolute Radio with Mike Shinoda from Linking Park taken on August 27th 2010. In the interview among other things Shinoda is asked: "What if Michael Bay calls you for TF3?" Shinoda answers: "I don't think we're working together (with Michael Bay) on TF3. We got a good run with the first movies but our interests lie elsewhere at this point."
Too bad, I'm a LP fan and I think they matched perfectly with the first two movies. I hope this is not final and they would be back for DOTM.
Here is the full interview. Go to 21:18 min.
And here is their first single (The Catalyst) from the new album which I think will fit nicely with the movie:
By the way there is a song titled Robot Boy in their new album but it's too slow for TF.