Lots of info via Twitter.
- There will be 6 episodes this year, including the Xmas Special. Then 8 next year. Jenna's character will first be seen at Xmas.
- Steven Moffat: "Amy & Rory will leave in a final encounter with [spoilers]* in ep 5. Not everyone gets out alive and I mean it this time"
*If you really want to know: