Sir Krist-
Can you tell us:
What school is this? What city are you planning to go to? Is it a scam? Do you know how much a US passport will cost ya? Why do you ask about a short time if you're going to be there two years?

Are you going to stay there for two whole years and not come back for school breaks, etc.?
How much Russian do you know, anyway? How much Russian culture do you know (sounds like not much from what you wrote).

Do you know what to shout when a band of gypsy kids surround you and start grabbing for your pockets? Can you order something from a menu?

I spent a month there in 2003, mostly Moscow, but about 5 days in Piter. And twice before that. Speak fluent Russian, read it too. Even so, I was wandering around in a daze (wonderful though it was), but managed to visit the Третьяковка and some other museums, parks etc. If you will be in M or SPb, I hope you have grown up in or around a large city.

If a cop spots you starting to enter Red Square and shouts Эй, налево! would you know what to do? If you sit down on a park bench and a lady on the next bench says Не курите! would you know how to answer? These both happened to me.

Get yourself in good physical shape. You will be walking 2-4 miles a day. Not kidding. Don't drink tap water. Get a good digital camera, learn how to use it before you leave. Extra memory and rechargeable batteries, and recharger.

Start posting here in Russian.

Here's a start for different менталитеты. You will receive your visa a week or so before you leave; they won't send it earlier. Until then, you will be wondering whether you will actually be allowed into Russia and whether you should have really bought that nonrefundable plane ticket. And you won't find out anything from the embassy, assuming someone answers the phone!

Just some food for thought. Also check out the forum on expat.ru. The other sites mentioned will be very helpful too. Удачи! When will this be anyway?