If you're completely new to the process and have no real idea of the kinds of schools out there (and their overall reputations), best place to start would be the published rankings: BusinessWeek, USNews, Financial Times. Don't take any single ranking as the gospel, but when you look across multiple rankings (which all have slightly different methodologies), you'll see some overall trends and consistencies.
From there, it's just a matter of scouring the schools' websites for info -- if you're a reasonably intelligent and perceptive person, you'll be able to pick up on which schools you think you'd like to apply to. From there, the best thing you can do is to talk to alums in your area (or even talk to as many people you know personally who have an MBA), talk to current students, and visit the school. This kind of legwork and research is far more useful than reading a directory or an "insiders guide" on individual schools - using primary sources (conversations you've had with MBAs plus school visits, info sessions put on by adcoms), you can form a much more informed opinion for yourself that gells with your own personal preferences. In other words, there isn't going to be a "one stop shop" guidebook that will be sufficient - you're going to have to pull from as many resources as you can, and rather than reading books, you're better off talking to people who have already gone through the process.
Alex Chu
alex@mbaapply.com
www.mbaapply.com
http://mbaapply.blogspot.com