Excellent tool, WCollins
I'll add my 2p recommending the Google toolbar, having installed it this morning. After testing it on several known pop-up-ad-generating websites, I'm very satisfied with its effectiveness. It's nice to to hear it's working well for others too. And the fact that it's free makes it even better!
I fully agree with PaperTiger ... the Page Rank "feature"
is not a good thing IMHO, so I de-selected that option right away. No complaints with anything else.