HabitForge is a Simple and Powerful tool Which helps you to help you develop a New Habit in 21 days by ingraining your daily routine via email check-ins.
Sign up for an account at HabitForge and you can create habit reminders. Tell HabitForge what you want to accomplish, phrase the question that will be emailed to you, and every morning you'll get a basic email from them that asks the question like "Were you successful yesterday at exercising after work?" with a Yes/No option beside the question. You check it off and HabitForge tracks your progress for 21 days.
In addition to the basic question, you can also give HabitForge additional information like the positive outcome of your new habit and the negative outcome if you should fail at it. Every three days HabitForge will include your "motivators" in your email to remind you why you're plugging away at your new habit. Check out the site for additional information and if you have a favorite tool for encouraging new habits, let's hear about it in the comments.
HabitForge [via App Scout]