Internet Addiction Test

"The Internet Addiction Test is the first validated and reliable measure of addictive use of the Internet. Developed by Dr. Kimberly Young, the IAT is a 20-item questionnaire that measures mild, moderate, and severe levels of Internet Addiction."

http://www.netaddiction.com/index.php?option=com_bfquiz&view=onepage&catid=46&Itemid=106