Hi Rob, I hope you enjoy your visit to St. Petersburg, it is one of my favorite cities. I spent a little over a year living in Russia, but in Vladivostok and Yaroslavl, so my advice about Russia is more general, though I have spent some time in St. Petersburg. In the major Russian cities the availability of goods is usually very similar to Western Europe, but things can be harder to find and more expensive. There will definitely be places to find 35mm and 120, but professional line kodak and fuji might be even more expensive then you are used to. Maybe not, that's just a guess. It was available rather easily in Vladivostok and Yaroslavl, which are much smaller cities.
The level of street crime is not really any greater than any other major city, and you should excercise a modicum of caution. Russians tend to dress more formally than Americans, so stick to long pants, collared shirts etc. Darker colors are more common. Wear dress shoes over sneakers. If you are going to bring a camera bag, something like a Domke 803 will attract less attention than a crumpler bag or a backpack (of any sort). You will probably be less touristy if you carry the camera at your side or on your shoulder than around your neck, but your mileage may vary. In general, just use your common sense and do what you can not to stick out. Don't speak really loudly in English, stare at some guy with a shaved head and swastika tatoos etc.
I have not had film through a Russian x-ray, so I cannot help you there. I have just put it all in a plastic bag and asked them if they would hand-check it, and they have each time.
Locations. This is probably better from someone who lives there, but here are a few sites:
St. Isaac's Cathedral (Isakovskiy Sobor) -- this is an amazing cathedral, very large, and at the top you have views of the entire city. I would not miss it.
The Russian Museum (Russkiy Muzey) -- everyone goes to the hermitage, but it is a big mistake to miss the Russian Museum. There are some fabulous native painters and artists there, and the building is a beautiful former palace. It is also more manageable than the Hermitage, which has something like 12 miles of corridors.
Petergof (Petrodvorets) is the Russian Versailles, and very worth visiting, but it is outside of town. There are plenty of tour buses ways to get there though, so if you decide to check it out it should not be that hard.
Aleksandr Nevsky Monastery (Nevskiy Monastir) -- The monastery is a quiet and pretty place. The graveyard is quite interesting, and many famous Russians are buried here -- Dostoevsky, Tchaikovsky, Mussorgsky -- the graves are quite interesting too. It might be an interesting place to shoot.
Actually,
www.saint-petersburg.com seems to have a really good sightseeing section, so you might want to look there as well. Other than that, Petersburg is just a great walking city and not that huge, so I would recommend walking as much as you can. The metro is really great as well, but you can get most places with your own two feet, and that makes sense, especially for a rangefinder user.
As for cameras, find yourself an Iskra if you can! Great little folder...
