It is common to represent status of an item in a GUI using the colors: red, yellow, green, to mean error, warning, and OK (or something equivalent). However, 7-10% of men have difficulty distinguishing between red and green because of color blindness.
So far I've looked at Color Scheme Designer which simulates how people with different color blindnesses would perceive a set of colors, but I'm interested in hearing how you have approached this problem and how successful it was.
Don't depend on the colours. You could apply symbols too (e.g. green tick, yellow triangle, red hexagon) or use text labels.
Use 'common' symbolic icons as well as colour to represent statuses.
Might be useful: Where can one find free software icons / images?
Found an interesting piece on designing for color-blindness.
One of the task-aways is never to rely solely on color. Always have some other indicator (text, icons) for a particular task.
Get any book about "accessibility" and you should have plenty of suggestions. They will more or less boil down to a simple principle: do not bind any information to color solely. That is, color should just be accompanying the information, which should never be conveyed by color only. I used Linux to develop one such application, and I used Compiz filters to simulate color blindness: very handy. As a side note, there are more types of color blindness out there, so pay attention to that too.
The company I worked for hired a colour-blind Swing developer - me!
Don't employ colour-blind operatives. ( Apparently the discrimination laws in the non-EU country we were selling the software in allowed this; YMMV )
Many UI designers start with black-and-white designs, and later add color to accent or emphasize, but only after the black-and-white design meets all the design goals.