My addiction to the internet has been growing and shrinking again for a couple of years.
The first step is acknowledging you have a problem, so way to go!
Then comes the hard part, changing your behavior.
Something I do to keep myself from surfing too much is reminding myself of what I'm losing by surfing. Social contact, health, education, sex, enjoying nature and just the whole world besides the internet.
Also think about what little you are gaining by surfing, a lot of knowledge you learn isn't applicable at all. For instance I've stopped surfing techwebsites and stopped reading techblogs, so now I'm less up to date to what the latest mp3 player is or what Google is up to. That didn't change my life, except that it freed up time
Forums can be interesting but a lot of it is just people ventilating their opinions in one or two sentences, which doesn't help you anything except eating away your life. If I go to a forum it is to help people or look for solutions for challenges I have or to read good information.
Try distilling what part of your online time is truly worth the time. Cut down your blog feeds, throw away half your bookmarks, call people instead of emailing them.
Some small tips: don't check your email until well in the afternoon, that way you'll actually have some good emails and you also process them a lot faster. Don't check your email more than two or three times a day. If it's urgent, people will call you.
If you'd like you can contact me through this forum, I might need some help, support and tips too
Good luck!