http://www.assmatrix.com/thick.htm
This guy's got his content niche shit together. It's hard to find a better guide on booty than that page.
This is a good primer for Ebony niche webmasters as well. Depending on who you market to (predominantly ethnic surfers or white surfers), how you present the ASS to your audience may make or break your marketing campaign.
Note: I used to do mostly ebony campaigns, now its a minor % of my traffic portfolio.