Helpful Links
100swimmingworkouts.com - Exactly what it says it is
Farther, Colder, Rougher - Great resource for open water swimmers
Swimming Science - A useful site for advanced swimmers and competitors
SwimSmooth - Wonderful place to find help with stroke and drills
Your Swim Book - Also geared more towards competitive swimmers, this is a great resource for gear reviews, more advanced workouts, and articles on just about everything
10km Open Water Training Plan - From Fiona Ford and Outdoor Swimming, an outline for a training plan for someone looking to compete in a 10K