I rellay like http://www.trainingbible.com. It's free to use just as a training log, and when you decide that you might like to have a little coaching, you can sign up for more services that help you plan your training program.
I've actually been using this one for a few months now (as a sidebar to my old fashion write it down in a small book) and I've found it worth the money to pay forit. Good support (Shasta is actually on forums.bicycling.com regularly) and the product seems to improve with each version. I've been able to see how I've done thus far and what the expectations are for the rest of my season.