High folk, I stumbled across these forums and I am looking for some help with shading a map that I have. I just got Photoshop CSS5 and I really don't know what I am doing. If someone can either help me out, or point me to a tutorial that could help me it would be appreciated.

This is the map that I have. What I am looking to be able to do, is shade in individual territorties in various colours but to have the colours transluent enough so that the names etc can be seen through the shading. I have managed to be able to solid fill in the various regions but not able get the fills translucent to see what is underneither them. I probably just missing some basic setting somewhere. Ideally I want to get the shading to the point where it allows for easy changing between colours (ie to represent different teams claiming different territories) that would be great!

If someone can give me step by step walkthrough or point me to another thread that answers this (i tried the search function but i kept getting a server error) I would be very thankful