I know this is a long shot, but I am wondering if there is a way to interface with iTunes and get anything like TrackID, time remaining, or access to the visualizer outputs.
Am I asking for too much (closed source program and everything...)?
I just got my LCD working and I'm looking for cool things to interface with it.
You may have better luck with gtkpod and similar open source programs 
http://www.gtkpod.org/about.html
They are open source so if they don't already have a plugin you can write one
iTunes actually has a pretty decent SDK. I've used the Windows version and was able to write a quick C# app that accessed all the things you were looking for, as well as control the playback (play/pause/next/etc).
Here's a link to the SDK http://developer.apple.com/sdk/itunescomsdk.html
And if you are using a Mac you can do that sort of thing fairly easily from AppleScript.
http://www.apple.com/applescript/
SerialPort X makes the Aduino available to AppleScript.
http://guide.apple.com/action.lasso?-database=macosguide&-layout=cgi_detail&-response=/ussearch/detail.html&prodkey=101787&-search