I was unable to find the answer how to change folder icon color on desktop. HOWEVER, I now know how to replace any folder icon or document icon on the desktop with another icon of your choice. The directions are a bit long, but they work. If anyone is interested, I would be happy to email those directions .
I was wanting to do this as well so I played around a bit. Not sure if this will help you though as this worked with Mac OS X 10.6.6 and Preview 5.0.3 but didn't work with Mac OS X 10.5.8 and Preview 4.2.
I was able to change the folder color with Preview.
Basically, copy the icon and change it in Preview, then paste it back in. It takes longer to describe than to do it
1) Get Info on the icon (like a folder)
2) Click on the icon to select it.
3) Edit (menu) > Copy
4) Open Preview
5) File > New From Clipboard
6) Tools > Adjust Color > Tint (and whatever else you want. Do this for all sizes)
7) Edit > Select All
8) Edit > Copy
9) Go back to the original Folder Get Info Window
10) Select the icon and Paste.
(You can also Save As to use the colored icon again)
I also couldn't change the Mail icon even after unlocking it and giving myself read/write access.
Folders and documents seemed fine.
Now my green folders have a green name and icon.
Hi Susan, sorry there was a long delay before I got back to you. I had other computer problems. You said you would be interested in an alternative way to change desktop icons. Here is what worked for me:
You can, change folder icons one at a time. To do this, first find a file with an icon you'd like to use for the folder, select it, and choose File --> Get Info. Click on the icon in the Get Info window and choose Edit-->Copy.
Now select the folder you wish to change and choose File-->Get Info for it. Click on the folder icon and choose Edit-->Paste.
Your folder will now be visible with your chosen new icon
Now select the folder you wish to change (Zippy on a folder above and below) and choose File-->Get Info for it. Click on the folder icon as shown below and choose Edit-->Paste.