For those users who are color blind, surfing the web can be a hassle. Being able to tell what text is a link, and what's not can determine the longevity of a visit. There have been a multitude of articles on developing and testing your website to ensure a color blind user will be able to distinguish the various elements of your site.

I came across a nifty little Mac App by Michel Fortin that allows you to take a look at what your site would look like if you were color blind. You can get the donationware application here at his website Michelf.com