Dance Etiquette: These guides to etiquette in a social dance setting are must-reads for beginners and excellent refreshers for experienced dancers:

• http://w4.lns.cornell.edu/~hs/pics/etiquette.jpg
• http://www.utdallas.edu/~aria/dance/etiquette.html
• http://www.hcs.harvard.edu/~hma-bdc/etiquette.html
• http://www.geocities.com/thirdstreetswingers/DanceEtiquette.htm

Dancing your way to better health:
http://www.webmd.com/content/article/107/108703.htm

Ballroomdancers.com (free online video instruction, step, music, tips, shopping, and more)
http://www.ballroomdancers.com/

Learn to dance Argentine Tango on YouTube:
http://www.youtube.com/results?search_query=TANGOCITY

James Marshall's ballroom page (styles, syllabi, history, music, links, resources, etiquette, competition help, tips, etc. etc.):
http://www.geocities.com/dronak/ballroom.html

"Much Ado About Dancing" social dancing handbook:
http://www.outdancing.com/Ballroom/

Centralhome dance resources (competitions, articles, steps, syllabi, DVDs, history, tips, and more):
http://www.centralhome.com/ballroomcountry

Excellent comprehensive collection of links compiled by the Swing and Ballroom Dance Club at UCSB:
http://orgs.sa.ucsb.edu/sbdc/m06links.htm

"Name that Dance"--how to determine which dance to do to a particular song and examples (many downloadable) of "typical" songs for each type of dance:
http://www.outdancing.com/Ballroom/preview/namethatdance.html

The official ballroom dance organization of the U.S.:
http://www.usadance.org

Inland Empire chapter of USA Dance:
http://usadance-ie.org

Competition levels primer by Megan Nix.

Ballroom 101 on the USA Dance website:
http://www.usabda.org/usabda/pdf/ballroom_101.pdf

Competition Survival Guide (originally from the USC Ballroom and Latin Dance team with edits by Harry Hsieh).

5 Competition Winning Tips from the American Dancer magazine published by USA Dance.

"Judge's Soapbox": "What I like to see, and hate to see, on the competition dance floor.":

• Eddie Simon
• Rosendo Fumero
• David Hamilton

Competition judging criteria by Corky Ballas, an ex-Champion who retired undefeated after 8 years.

Brian's (from Cornell) Competition FAQ:
http://cornelldancesport.org/faq_comp.php

Detailed syllabi, including descriptions and very handy diagrams of many of the figures:
http://www.umich.edu/~umbdc/frame3c.htm

Excellent collection of Standard and Latin videos of high level dancers at Truong An Ballroom Dancing Club (look under the "Related" tab for more videos):
http://www.youtube.com/watch?v=80xYh_lZsSQ