You've not stated which web browser you're using. Firefox automatically blocks the vast majority of pop-ups, simply using it in its default state. (i.e. you don't have to change any settings. You simply use it 'as it comes').
Firefox is used by the vast majority of the 'regulars' on AB's Technology section, simply because it's far superior to Internet Explorer. If you're not already using Firefox, now's the time to switch:
http://www.mozilla.com/en-US/firefox/
Sometimes adware will generate pop-ups which are actually stored on your PC, rather than sent through the internet. If you're not already running Ad-Aware or Spybot, on an occasional basis (perhaps once per week), you should download at least one of them now:
http://www.lavasoftusa.com/products/ad_aware_f ree.php
http://www.safer-networking.org/en/spybotsd/in dex.html
Using Firefox, in conjunction with Ad-Aware or Spybot, you shouldn't really need any additional software but there are plenty of free pop-up blockers available on Download.com. Here's one of them:
http://www.download.com/CBlock-Pop-Up-Blocker/ 3000-7786_4-10443590.html?tag=lst-0-5
For more, search here:
http://www.download.com
Chris