There is a detailed 1960's Soviet biography of Lenin which can be bought on Amazon for cheap:
http://www.amazon.com/Vladimir-Ilyic.../dp/B000GLD05U (I have it but have not yet read it)
There's a rather brief Stalin-era biography of Lenin online here:
http://sovietlibrary.org/Library/Uni...0Institute.pdf
There are a number of bourgeois biographies but I cannot comment on their quality, except to say that Robert Service's is probably to be avoided until you read others first, since his three biographies of Lenin, Stalin and Trotsky share the distinction of being denounced by everyone, and that Dimitri Volkogonov's is interesting due chiefly to his access to archival materials, since he is otherwise strongly anti-communist and attacks Lenin any chance he can.