Variety has an article about the major studios planning release dates several years in advance and it mentions this about Bond 23.
While director Marc Forster is just now working with writers on the next Bond film for 2008, there's a 2010 date for the one after that.
That 2010 Bond pic exemplifies the latest trend. Many studios, with dates lined up for '09 and the year after that, have set marketing and merchandising plans in motion and have started talks with visual effects houses. In many cases, the only thing they lack are a director, stars, script or even a story outline.