VDOT - Distance/Time (Attackpoint)
VO2 Max & Purdy Points - Distance/Time (Run-Down)
Race Time Estimator with Adjustible "Aggressiveness" Settings - Download (Greg Maclin)
Distance/Time/Mileage - Uses data collected by "Jim2" - Download (Greg Maclin)
Marathon Course Time Predictor - Download (Greg Maclin)
Boston Marathon Predicted Times - Download (Greg Maclin)

Based on your input for two out of three variables (Distance/Time/Pace), calculate the third:
Distance/Time/Pace (Marathon Guide)
Distance/Time/Pace (RunningPaceCalculator.com)

Run/Walk Calculators:
Gallowalking Pace Calculator (Mike Williams)
Gallowalking Pace Calculator (Scott Glazer)
Run Walk Pace Calculator (Joe Ely)

Track Info:
Track Calculator (Calculate distances, lap times, pace, etc.)

Nutrition:
Runner's Nutritional Calculator (McMillan Running)

Heart rate:
Training and Racing Heart Rate Zones - Download (Greg Maclin)

A large collection of running tools for calculating training/race paces, VO2max, heart rate training, weight, and diet:
Distance/Time, VO2 Max, HR, Weight, Diet (Running for Fitness)

WMA Age Grading (see how you rank):
WMA Age-Grading (Howard Grubb - 2006)
More Info About Age Graded Scoring

WMA Notes:
100% = Approximate World Record Performance
90%+ = World Class Performance
80%+ = National Class Performance
70%+ = Regional Class Performance
60%+ = Local Class Performance