A potential entrant into next year's Tampa Bay Marathon Swim sent an email to me asking some basic questions regarding equipment, rules etc. Here are the links to information about our event, followed by links of some of the world's best open water swimming websites. I put the list together in about 3 minutes, so please forgive me if I've not listed your site.

Distancematters.com/
http://distancematters.com/entryform.pdf

Openwaterswimming.com
US Masters Swimming
Santa Barbara Channel
New York & Manhattan
OWS Wiki
US OWS
Fresh Water Swimmer
CSA EC
Open Water Swimmer
ED .net
EC .com