I solved it myself by going to applications folder, then secondary click on iTunes.app, click on "Show Package Contents" and going to Contents/Resources
(From there, I copied both "iTunes_leopard.icns" and "iTunes.icns" to a safe place, just in case).
Again, I copied "iTunes_Leopard.icns" to another place, like desktop, and I changed its name to "iTunes.icns".Then I moved it back to Resources folder, where I had to autenticate as administrator, and accepted to replace the existing "iTunes.icns"… and Voilá!
It works for me, once and for always (and for all the rest except you, it seems) since I did what I told you. Never need to look out for another icon, the one you need is inside the app at iTunes/Contents/Resources/iTunes_leopard.icns… Probably if you re install iTunes, or update to a new version, you may need to do it agian. If it works once, has to work ever.
You may need give more details, for instance, what have you done after you first notice the issue again, specify your iTunes, Mac and Mac OS versions, upload some screenshots, of iTunes.icns and iTunes_Leopard.icns' "Get Info"…
Thanks Cauac, your solution seemed to work for me! 2010 Mac Mini.10.6.8, still running iTunes 10.7 (resisting v11 as long as I can), The icon is back in the Force Quit menu and the Open With contextual menu, and it's showing up again normally in iTunes get info.
I wasn't having any of the Allow Incoming Network Connections repeated messages like some posters reported.
When I made copies of the iTunes.icns and iTunes_Leopard.icns files and got info on them, I noticed that the Leopard one (the one I removed from the word Leopard from and replaced inside Resources) was 512x512, while the iTunes.icns version was 1024x1024. Doesn't seem to have affected anything though.....none of my icons look grainy etc.
All is well in OCD land again !
Your welcome, dmilazzo.
I wish downgrade to iTunes 10.7; 11 is nice, but it annoyingly opens always with its window wider than my macbook display, and lost some nice features. Not fixed on 11.0.1, hope next upgrade fix this bug. It seems these kind of bugs happen so often, every new iTunes release…
You do well staying with 10.7.