We use Training Peaks online software. You'll be asked to sign up for a free account during the checkout process.
At it’s most basic level it’s a training calendar that enables you to view your planned workouts and record your completed sessions. If you choose to get technical, you can analyse your completed workouts with a wealth of useful tools. It can be used on PC, Mac, smart phones and tablets and it syncs to most commercially available training devices including Garmin and Polar. You can also set it up to email your workouts daily at whatever time you choose.
Training Peaks is as simple or as complex as you want it to be. It enables us to set you in-depth training plans in a way that other formats do not. For example, we can attach images and descriptions to a swim workout to describe your swim technique drills properly.
You can also set your own start or end date and apply your training plan to your calendar as many times as you like in the future.
This link will give you 5 simple steps for getting started with Training Peaks.