How to block Facebook ads
Facebook's new ads come in two forms. Social Ads are based on your profile. Beacon ads come from other sites when your friends do something there. Enterprising JavaScript nerds have already reverse-engineered a way to keep them out of your face.
To block Beacon ads, just add the URL http://www.facebook.com/beacon/* to your ad-blocking tool. If you don't have one, these instructions will set you up on Firefox.
Social Ads will supposedly use the news feed URL http://www.facebook.com/stories.php?filter=28. We at the 'Wag haven't seen any yet. But hopefully they'll be adjustable via the News Feed Preferences page, as are other numeric categories. If Facebook won't let you customize your feed not to show any #28 items, expect a Greasemonkey hack to appear shortly.