There is a simple and quick way to change the iTunes icon with the name of your song's album or the track of the songs. Simply follow these steps:
Firstly, please download DockArt, it is a free plugin for iTunes that compatible with version 10.4 or higher.
1.After Dock Art is downloaded, then quit iTunes.
2.Unzip the DockArt2.zip file
3.In your Desktop, hit Command+Shift+G to bring up the “Go To Folder” window and enter the following directory path:
3. Drag the ‘DockArt.bundle’ file into that folder
4. Reopen iTunes, then playing a song, you will see the iTunes icon has been changed with the playing song album.
5. Finish and congratulation!
Source: Cult Of Mac.