I just wanted to add; The pitch call/game management section in Jerry's book is not just an overview but goes pretty in depth, about 1/3 of the book. Anyone with a catcher, of any age, should seriously consider getting this resource.
Again, if there are any other resources please let me know.
Another must have book for catching instruction - The View From Behind the Mask by Todd Coburn and Roy Anderson. This book has a good section towards the end of it on game management. Lots of photos with correct and incorrect techniques explained.
I primarily use their information, Ian's and Joe Wilkins when I instruct our catchers and I wasn't even catcher when I played ball.
Other good websites:
http://www.joewilkinscatching.com/
http://www.catchingcamp.com/ - the DVD sold here is very good by the late Dave Weaver
http://behindthemaskcatching.com/
http://www.webball.com/cms/page1157.cfm - Richard Todd
http://brentmayne.com/ (not free content)
http://advancedcatchingconcept...stead.com/index.html (geared towards girls softball)
http://www.chadmoellerbaseball.com/ (not free content)
http://www.mycoachonline.com/baseball/catching.lasso
http://www.simplicityofcatching.com/
I have several more, but these should be pretty helpful.