Instructions
Make sure your PSP has custom firmware (CFW) installed. A simple web search will direct you to install locations and instructions.
Install the NitePR cheat engine on your PSP.
In "Resistance Retribution," create a new clan. Give it a name and a tag, but don't save the clan yet.
In NitePR, go to "Search" and highlight "Find Exact Value." In the ASCII section, four dots appear. Under the first dot is an indicator. Scroll the indicator until it matches the first character of your clan tag. Repeat matching the other dots with the characters in your clan tag until NitePR finds an exact match. Select the match. A New Code screen appears.
In the New Code screen, look under the section "HEX." The last two digits are the code for the color. Change the code as follows: 10=White, 11=Green, 12=Blue, 13=Yellow, 14=Gray, 15=Red and 16=Orange. Press the "O" button. You should return to the main screen of NitePR.
In the main screen of NitePR, go to the section "Cheater." Turn on the codes. This applies the new color code to the clan tag.
In "Resistance Retribution," save the clan. The color of the clan tag appears in the color you specified.