Yes, it's called "nodofollow". It's a plug in for firefox. All the nofollow links are highlighted red, but all the "active" links are highlighted too (blue) so it's easy to see who's playing nice and who's not.
I switched to this not to long ago to check nofollow/dofollow tags and really like it. One of the tools I really like about SEOQuake is that you can sort search results by PR. Comes in handy for blog commenting.
Can anyone explain? I have several sites that are showing backlinks from PR8 sites with the "NoFollow" tags. I thought we were waisting time posting to a site or directory with "NoFollow". I am a pretty good SEO and have practised embeding links succesfuly pointing to my clients websites for link juicein these sites.
Try nodofollow extension for firefox https://addons.mozilla.org/en-US/firefox/addon/5687 It is the easiest way to check do-follow.