Outside of all of the ways in which you can intercept and block traffic during the DNS validation or with the components prebuilt into your web browser of choice, a variety of commercial and free pop-up blockers are available on the net. The methods above are effective at reducing the number of pop-ups because they block access to the ads that cause them. But there are others that you can use.
One of the best choices for free pop-up blocking is the Google Toolbar. It is proficient and allowing you to switch between allow and deny modes while providing a host of other features. But keep in mind that Google has purchased DoubleClick which is known for collecting as much information about people and their web habits as is possible. It has the potential for being a spyware clearinghouse. In fact, I block access to all known DoubleClick sites to prevent their invasive tracking behavior.