I wouldn't fret about dialects, etc. Just learning the basic Russian language will do you fine. Everyone speaks Russian over there, even if they also know Chuvashian, Ukrainian, etc.
Needn't give yourself fits over tenses of nouns, etc. In other words,, the general word for book is kniga (kuh-NEE-guh). Even though it should technically change depending upon who is speaking to whom, the truth is if you just say kniga all speakers-of-Russian will know that you mean book.
Might start here:
Russian Lessons .Net - Free Online Russian Language Lessons.