http://forums.digitalpoint.com/showthread.php?t=18243 http://forums.digitalpoint.com/showthread.php?t=1045422 http://forums.digitalpoint.com/showthread.php?t=111766 http://www.webmasterworld.com/forum89/7872.htm http://www.webmasterworld.com/forum89/12150.htm
If you visit the Google AdSense Program Policies site, you'll see that Gambling sites aren't allowed: Google AdSense Program Policies Look under "Site Content" section. Like LifePlayer mentioned, use gambling affiliate links instead.
Just to add details to what Proxima and lifeplayer wrote, it's not just sites where people gamble that aren't allowed, but any site with "Gambling or casino-related content", so poker strategy would not be allowed.