Useful links:
Little League district 4 umpires: http://www.llcad4.org/d4_umpires.html
Little League international umpires site: http://www.littleleague.org/umpires.htm
Little League international umpiring resources (need to register): http://www.littleleague.org/umpires/urc.htm
Rules quiz site: http://www.thetasoft.com/quiz/quiz.aspx

Articles of Interest
How to argue with an umpire  http://www.fld9.org/documents/HowToArgueWithAnUmpire.pdf
Getting Along with Baseball Umpires:  http://www.momsteam.com/successful-parenting/getting-along-with-baseball-umpires-nine-tips-parents-coaches