Winning One Pocket and Shots, Moves, and Strategies, both by edited by Eddie Robin, are considered the bibles of One Pocket.
Recommended, but expensive.
Upscale One Pocket by Jack Koehler is good for beginners.
I recently got the Power One Pocket DVD from Fast Lenny here on AZ.
You might be better off buying DVDs from Accu-Stats. Tournament matches can be pretty eye opening and there are a bunch available.