Haha. He won't be getting any playing time then. I don't think we'd be stupid enough to sell him to a direct rival. If we were to sell him, we should get at least 10 million pounds for him; the 8 being quoted is the release clause in his contract if I am not mistaken.
I really don't see the purpose of selling him. We have seen what Inzaghi has done this season, and Trezeguet's age is not a really a problem since he is a poacher, a lethal striker inside the box. I say retain him, get an option on Benzema, and then buy him after the 2010 WC.