It looks like Horner signed with Rock Racing.  That's the old rumor that has shown up again.

http://www.bicyclenorthwest.com/

A previous Velonews article on cross quoted Horner as saying he was done with Predictor.  Slipstream just announced that they finalized their roster.

While I'm sure Horner will be a terror in the US next year, I'd rather see him breaking legs in Europe.  I still don't think he has reached his full potential on that side of the pond.