Hi we did this cruise July 1, 2006 and it was one of the most remarkable trips I've ever taken. Never in my wildest dreams did I ever think I would have gone to Russia.
In St. Petersburg and Berlin we used private tours companies.
Helsinki, Stockholm and Copenhagen we did on our own, but in Copenhagen we did have do a private walking tour I booked on our own. I have a wealth of information on the trip.
Estonia and Lativa we did Celebrity Shore Excursions. Can't remember, but I'm sure I'm missing something.