iTunes Uses Bonjour to Announce Itself to Apple Remotes
This will come as a surprise to precisely no-one, but it looks like iTunes announces itself over Bonjour when you turn on "Look for iPhone and iPod Touch remotes" under the advanced preferences. Above are my iTunes Remote details that popped up in Bonjour Browser after I clicked the iTunes' check box.
Sadly, there are no remotes to read the signal just now, but it does seem likely that some enterprising hackers may someday be able to use this info to hack together iTunes remotes for other platforms besides iPhone 2.0. Because, you know, there are still going to be people out there that don't use the iPhone. :D