It's definitely on this year!! YES!
From the Red Bull Stratos website yesterday:
"The jump will happen sometime this year. I know you’re thinking, “how am I going to mark it on my calendar with a vague answer like that?” I can tell you the team has made really good progress in a matter of months, but they need to run more tests. We’re launching out of Roswell, NM so the weather will be another determining factor. Believe me, when it’s time to launch we’ll give a big shout out."