This may come as a surprise to the more serious aficionado's[ED Wow did I butcher that spelling!] of fantasy football, but I take a very cavalier approach to preparing for my drafts.
I begin with a magazine or two and peruse the rankings for each position. I do not get to the nitty gritty until very close to the draft.
given the obsession with football, almost every angle gets covered by the time I draft.
At that point, I will have developed a list of players I will reach for begining in the 5th or 6th round.
Right now, I have the fanatsy football issues from Sports Illustrated and ESPN. Soon I will sign-up for Yahoo! fanatsy football for access to its rankings.