I just came across this great WikiHow article and had to link to it. I know several people who could benefit :-)

http://www.wikihow.com/Stop-Swearing

How to Stop Swearing

Swearing can easily become a habit and is generally a bad habit. It is reinforced by the company we keep, the people we are trying to identify with (e.g. the "in-crowd"), parental examples and workplace behaviour. Parents must be extra careful to curb swearing tendencies as they are the first and principal cause of swearing children. If you don't want people to get the wrong impression of you and you are tired of swearing instead of speaking clearly, then this is a short guide to helping you to think about why you swear and how you might be able to curb the habit.