The next 3 links have information about modern square dancing:
1) What is Modern American square Dancing
3) 70th National Square Dance Convention Highlights
The following links to other organizational groups:
SEMCA - The Southeastern Massachusetts Coordinating Association Inc.
NESRDC - New England Square and Round Dance Convention
The following links are a good source for helping to learn some of the square dance calls.
The site has basic/mainstream/plus...and higher level calls. GOOD DANCING!
http://www.opensquares.de/basic.html