I did a lot of research on this topic this year because I wanted to do my own rankings. You will find a lot of opinions and it can become quite confusing. The best information for starting out I found in this article from a link on one of the posts on here:
http://www.insidethebook.com/ee/index.p ... _baseball/
The basic steps are
1. Reduce your list to what you consider draftable players for your league. My list contains roughly 190 hitters and 130 pitchers
2. Take standard deviations for each scoring category, separately for hitters and pitchers of course. This is easy for counting stats like HR's or K's and a bit more involved for average stats like BA and ERA. See the article for help.
3. Add up the the points in the scoring categories for each player.
Then you have some rough numbers to rank your players, but you haven't taken into account position scarcity. To make things simple, I sorted my rankings by position. For my 12 team league that starts one 1B, I set the 13th rated 1B's point value to zero. I then added that same value I used to zero him out to all of the other 1st basemen. Do the same for each position but make sure to take into account how many active spots your league uses for each position. For example, my league starts 5 OFs, so I set the 61st OF to zero points. For pitchers, I estimated 6 SPs and 4 RPs, so I zeroed out the 73rd SP and 49th RP.
Now you have points that are adjusted (somewhat) for position scarcity.
I went a bit further with this myself and continued to tweak my rankings with more calculations and adjustments, but this is one way to get you started.