A number of members suggested some great Lightroom books you can get at most local book stores or by these direct links to Amazon:

The Adobe Photoshop Lightroom 3 Book for Digital Photographers (Voices That Matter)

List Price: $54.99

Price: $22.99

You Save: $32.00

The Adobe Photoshop Lightroom 3 Book: The Complete Guide for Photographers

List Price: $59.99

Price: $19.35

You Save: $40.64

Adobe Photoshop Lightroom 3 - The Missing FAQ: Real Answers to Real Questions Asked by Lightroom Users

List Price: $45.95

Price: $14.49

You Save: $31.46

Happy Lightrooming!