Ethnologue: Languages of the World An extensive research resource on the world's 6,700 languages from the SIL International. Includes language maps, bibliography and computer resources for each language.
The European Library Provides access to national libraries in Russia, Poland, Ukraine etc.
Learn Russian A free language resource hosted by RT, Russian language television network.
The Online Books Page Offers access to digitized books. Search by LC call number PG (Literature—Slavic).