US Lacrosse is a great resource for information: https://www.uslacrosse.org
US LAX Magazine is a great way to stay current with the lacrosse community. It features tips on training and lacrosse, features players and coaches, and provides other helpful information. http://www.uslaxmagazine.com/
If you haven't attended LAX Con, you should. It's a great way to network with other coaches, hear from some of the best coaches, get certified as a coach, and to learn more about the game.