No, David Tennant has left, his last episode was on New Years Day, Matt Smith is The Doctor now.
No.
No, Matt Smith.
yes.he was in it in series 5 with david tennant
David Tennant isn't doing series five, Matt Smith is taking over as the eleventh Doctor at the end of the year, his companion is Amy Pond played by Karen Gillan and Steven Moffat is taking over from Russell T Davies, so it will most likely be totally new characters of his creation from now on. If you mean clone Doctor and Rose then I doubt they will have 10.5 in the new series because it would over shadow Matt. Billie Piper does have a small role/cameo in one of David's final episodes though, but it will be Rose before she met the Doctor so she will have no idea who he is.
Matt Smith plays the Eleventh Doctor in Series 5
The New Doctor Who Starts on 3rd of April. They are doing a count down, on the Doctor Who BBC website. It's a pity David Tennant has gone.
Yes, he has signed up for series 5 which will be shown in 2010. There won't be any series in 2009 as he is taking time out to tour with the Royal Shakespear Company. There are rumours that he will regenerate into a new doctor near the end of series 5 though, which I hope isn't true :)
No Jack is not in series 5.
series 5
David Tennant will continue as The Doctor for the several specials which will be shown during the 2009 period. Matt Smith began filming as The Doctor on 28th July for series 5, which will air in 2010.
No she was not in series 5.
According to many articles, David Tennant said he wanted to be an actor already when he was 3 years old.