Instructions
Open Steam and then click the "Friends" tab.
Click "Change Profile Name."
Type your user name and insert "^" and then a number before a letter to change its color. You can change a specific letter or letters or modify the entire user name. The colors -- beginning with 1 -- are red, green, yellow, blue, cyan, purple, white, gray and random. For example, if your user name is "AwesomePlayer" and you want to change "Awesome" to cyan and "Player" to purple, you would type "^5Awesome^6Player," without quotes.