Following the engagement between Prince Albert and Charlène Wittstock yesterday, the French newspaper Nice Matin published a short interview with the prince in today's edition. The Sovereign Prince informed that the wedding is going to take place during the summer of 2011.
The exact date will obviously be published later. In other words, there will be plenty of time for Charlène Wittstock to adjust to her future position as the principality's first lady.
Prince Albert seems to have much more contact with the other royal families of Europe than his father used to, so I think we can expect a large gathering of royals in Monaco at the wedding next year.