When shopping for lenses, compare lens sharpness using the Lens Image Quality Tool at The-Digital-Picture.com. This tool lets you compare lens sharpness on different cameras at different focal lengths.

Syl Arena's book "Speedliter's Handbook" helps explain a lot about cameras, strobes, and more. I highly recommend it. Expose for your background, then light your subject!

Strobist.com is a great place to continue your education about strobes. 

SHOTKIT

Want to peek inside the bag of tons of professional photographers? Shotkit.com is a great place to see what gears the pros use!

Roberto Valenzuela's Books

Roberto Valenzuela has written several insightful books about his photography techniques. He does a great job teaching the reader how to be more thoughtful about posing and light. One of my favorites is "Picture Perfect Posing."