One Tree Hill creator Mark Schwahn has signed 3 production deals, one of which pretty much ensures that those Tree Hillers will be sticking around for a 7th season.
The aforementioned deal guarantees that Schwahn will remain a showrunner and executive producer with Warner Brothers (who produces OTH) for another year. While this could technically be for any show, it makes sense that it would be for One Tree Hill...
Schwahn's other deals will allow him to create a new series with CBS Paramount TV which will focus on the music industry as well as a related deal with CBS Records. In case you hadn't noticed, Schwahn (a one-time band member) likes music (and I think the generally excellent One Tree Hill soundtracks prove that he knows what he's doing).
So, great news all around for Schwahn and OTH Fans!
Source: TV Guide