You can ad "No dofollow" adon in firefox. when you right click on any link, you will find a option no follow in snipt and click on that all nofollow links will become red and do follow links will become blue
I also use the nodofollow Firefox tool and found it much quicker and easier to use than viewing the page source for this information.
both are backlinks that doesn't make much difference that what is. Both help in ranking. do-follow help in PR while no-follow doesn't help in PR.
download seoQuake it also tells whether its nofollow or dofollow, and it is available for all browsers