Hello,
I am wondering if any people will be traveling on the Emerald Princess May 12, 2012 departing from Copenhagen who are interested in private tours of sites in St. Petersburg. sites to include St. Petersburg, Hermitage, Catherine's Palace and Yusupov Palace?
Make sure you understand the Russian visa requirements if you take a private tour. When my parents went, if they weren't going to be with the cruise's excursion, they had to have a separate, costly visa. But to answer your question, you might get answers at www.cruisecritic.com. Most people here are more the DIY travelers or Rick Steves tour people, rather than cruisers.
Your best bet is to go to cruisecritic.com, create an account (just like this site), and check the roll-call forums. If there isn't one established for your cruise yet, you can start one. When I cruised to St. Petersburg, there were about 50 regulars on the roll call, plus others that didn't engage but checked in. We had a reception on the first at sea day of the cruise. One ambitious lady organized a tour for about 30 people, then a second for another 20 that couldn't get into the first. My wife and I, instead, went directly through Alla tours. They put us with 8 others passengers for a "strenuous" two day tour. Strenuous essentially meant lots of walking and no lunch break (we packed a lunch off the ship) in a ten passenger van with a driver and guide. Have fun. Don't listen to Princess, they go to great lengths to make you believe you won't be able to leave the ship unless you take their tours - it's absolutely not true, just have the things your tour tells you to bring.