While I am in the middle a few color studies to develop a palette for interactive programs requiring low-vision accessibility (which I also will soon publish), I have come across many online tools for sight simulation. Firefox's Addon Colorzilla and ColorSchemeDesigner3 are among the most helpful. But the most interesting I found was ColBlinder.
Just a tip with abiding by non-exact descriptions -- I have referred to colors by name to designers, non designers, and clients, and I can't think of a situation where I didn't have to pull out a Pantone book or provide a hex code anyway.
Me ke aloha,