Professional Keying with Keylight is the latest video training from Toolfarm's Expert Series. It takes you through pulling tight and clean keys with Keylight in After Effects and shows you how to overcome problem areas like wispy hair and textures on edges. There's also tricks for making composites believable and a greenscreen shot and background plate, for $39. An excerpt reminds me of some of Matt Silverman's methods for developing mattes procedurally in the now defunct Commotion.
And available soon is Greenscreen Made Easy: Keying and Compositing Techniques by Jeremy Hanke and Michele Yamazaki. Harry Franks says, "If you are looking to get started with greenscreen production as a hobbyist or a professional, this book has everything you’ll need to hit the ground running. If you are a motion designer and visual effects artist with little exposure to the “other world” of production, including cameras and lighting, you’ll want to grab this book for a great primer on the subject." For flavor, see also an earlier article by earlier article Noise and Artifact Suppression Tips by Michele Yamazaki.
More on keying can be found in the recent AEP post Greenscreen Primers.