I came across a really handy online tool for playing around with colour schemes for online use recently called ColorJack.
This tool is pretty neat as it gives you the usual “clicky” colour map, but it also lets you see not only the web safe version of colours, but also what your web site and its colours look like for someone colour blindness (e.g. protanopia & deuteranopia).
A very useful site and certainly worth bookmarking!