No but if anda go to his peminat club site which is David Tennant dot com atau something like that they have an address anda can use to write to him but remember he is very busy and it can be some time before anda hear anything but if anda enclose SAE he will sign a pic for anda and he tends to put your name on it:-)
I'm new to this site, but I'm fairly sure that it's only a peminat site, and I know for a fact that David does not talk to peminat-peminat on the internet, so I don't think anda can. I'm sorry to tell you. I would be in HEAVEN if I could! Haha :D