It's not a trailer for the first episode, it is a preview of the next series, but yes, it was the one shown after Confidential.
Personally, I'm glad Tennant has now gone, I don't think the last two episodes were that great, and nice though some bits were, we had a big group goodbye at the end of the last series, so why re-hash it again?!
Don't get me wrong, I think Tennant has been an excellent Doctor, but the sullen, brooding Doctor that we've had for the last year is one I can live without.
I'm looking forward to seeing Matt Smith and Steven Moffat breathe some cheer back into the series.