While it [ the Bible ] doesn't mention pornography, what goes with it—lust—is identified clearly as a sin.
Chapter 4 Page 55
As with any other sin, God is there to help... But breaking the habit is very difficult by just by telling yourself not to. First off, you need to ask God for help. That’s important. Then, throw away pornographic material and avoid looking at sexy pictures, films, or anything that stimulates lust. This is one of the sins you run away from. Further help can come from sharing the problem with someone to encourage you when you resist and pick you up when you fail... having a friend you trust, preferably a Christian, who you can talk to about this is very important.