Omg! built in color codes available to everybody!? That is right! now, here is a guide.
Mac
Press alt+6 to get a § in MC chat. Then after that you select a code by pressing a number, 0-9, or a letter, A-F.
PC
No idea how to access the § right now. I will look up how to do it when I get up in the morning.
Code list:
0- Black
1- Dark Blue
2- Vtn Green
3- Donor Chat Blue
4- Dark Red
5- Purple
6- Orange
7- Rsd Gray
8- Gray
9- Donor Name Blue
A- Lime Green
B- Really light blue
C- Light red
D- Pink
E- Yellow
F- White
Has fun with colors :O