Not Weber specific, but a couple of books that first got me excited about live fire cooking were "Real BBQ" by Vince Staten and the legendary "Smoke and Spice" by Cheryl & Bill Jamison.
Lately my biggest literary influence has got to be Steven Raichlen. As well as being an incredibly popular author, he's a Cordon Bleu chef and James Beard winner who also has a masters degree in archaic cooking methods. His 'elemental' approach to grilling has me rethinking everything I thought I knew.