- Quit iTunes 10. Make sure you quit it from the dock or the menu bar on top.
- Go to the applications folder, right click on the iTunes app icon and click on ‘Show Package Contents’.
- Download this file iTunes10colors.zip and extract it. There’s a file inside ‘iTunes.rsrc’.
- Replace the one in the package contents with the ‘iTunes.rsrc’ you just downloaded.
That’s it. You now have your colorful icons back!
Thanks to Uneasysilence for the discovery
Also check out the following guides for iTunes 10:
Fix vertical Maximize/Minimize/Close buttons in iTunes 10 on Mac
How to disable your Ping Account in iTunes 10 [Guide]