Особенно понравился раздел "All Roads Lead to PVU":
The Central PVU (formerly UVIR office), under the authority of the Ministry of Internal Affairs, is responsible for registering, extending, or modifying Russian visas. There is a central PVU office in virtually every Russian city. Smaller, local PVU (or OVIR offices --Otdeliniye Viz I Registratsiy) are located throughout Russia. Pay special attention to the destination written on your visa. If your sponsor and final destination are not in Moscow, then you cannot address visa problems in the capital. Russian officials will require that you travel to your destination to sort out your visa problems. Americans in possession of Student or Guest visas must find out from their sponsor which local OVIR office is responsible for their visa. Commercial and Transit visa holders must go to the central PVU. There is a slim chance an officer at PVU might speak English, and the process is generally long and cumbersome.