If you want to change the color palette of your OSX terminal you’ll find that you can’t change the ANSI colors set from the window properties (command+I).
That’s not true, you can open a color palette and drag the color to the set you want to change, for example the blu of the directories is horribly dark and quite ureadable on a black backgroud.
See a short screencast in this page (from Macworld.com)
UPDATE: Thanks to “volte”
here’s a link to Ciarán Walsh’s Blog who (as always) found THE solution for Leopard.