Alright, so nothing much is known about the 2009 specials except:
1.) The Cybermen are in the Xmas one
2.) Georgia Moffat (Jenny) will be returning.
3.) RTD has written two of them and has co-written the other two
Thats all I could find out. Once again, feel free to add. Here are some theories I heard:
1.) River Song will be returning
2.) There will be two Xmas specials, an easter and a Halloween one.
3.) It will feature the Time war
4.) DT will regenerate
5.) Queen Elizabeth (from The Shakespeare Code)
6.) One of the four episodes will be aired in Egypt
7.)David Tennant/Paul McGann Doctors episode (Although I doubt that)
8.) Master Returning (Once again, doubt it)
9.) Sally Sparrow/ Midshipman Frame returning
10.) The Valeyard
11.) The Black Guardian - Halloween Special
12.) The Ice Warriors will be back
13.) Featuring the Zygons and Sea Devils (Something to do with sinking Venice? :))
14.) One special is to be called "Ghosts in the Machine"
Well, I could go on but you get the point. There is a lot of substance for these specials and even though RTD is writing two of them, my expectations are rising.
As for David Tennant, my guess he will be regenerating at the end of these specials. We can all hope for him to take that offer to stay on but he must have hundreds of other ones and wants to advance in his acting career. Who can blame him. Oh well, he was one of the best, all though pretty grim sometimes. I'll be sad to see him go is he does, but at the same time, excited for a new Doctor. Well, we will just have to wait and see. As for who is replacing him, well thats a whole different topic.
On a completely different topic, Do you remember in "The unicorn and the Wasp" when Agatha Christie asked The Doctor, he was talking about how his friend had been captured and he was walking through a rain forest with a quiver of arrows slung on his back. This was a flashback. Was I not paying close enough attention or something? Or was this an intentional set up? The only reason I'm asking this is because I've never seen anymore talking about it. Anyway.
Alright, I really doubt some of these theory while some are completely believable. I'll let you be the judge on that, and feel free to add your own! (If I left any...:))
(Yes, I am one of the four fans of DW in Canada :P)