Result from the search on this issue:
"Google has always prohibited the advertising of things like bingo, poker and online casinos. However having looked at this issue very carefully and considered the views of our users, we have decided to extend our policy.
We will no longer take ads for sites that promote gambling related content or gambling tutorials or whose primary purpose is `playing for fun', gambling or casino games of skill. While we respect people's differing views on gambling - and support freedom of expression - we believe that this new policy is simpler for everyone to understand and more in tune with users' wishes."