The Couch to 5K program is great, but the ActiveTrainer site is not responsive to change in that program. If you miss a workout, and want to move the REMAINDER of the plan outwards to reflect that change, it just does not work. I asked for help, and got a canned answer about how to move my start or end date, but what I wanted to do was keep the start date the same and adjust the remainder of the workouts so that it reacted to the change. I asked for help again and got a message that ActiveTrainer had a higher than usual volume of tech support requests, and they never did get back to me.
I pretty much felt that I wasted the $19.95 for the Couch to 5K program.
Only use it if you are positive that you will be able to adhere to it 100%. Otherwise you just have to fudge and change dates on your own, so that the reminders and listings on the calendar are then meaningless.