The 10.2.2 update (available from Software Update) for Mac OS X disables the ability to search for song files on iPod via the "Find..." (command-F) menu item.
Update:
silicondiode provided a link to the ReadMe, it points out the enhancement:
Improves the Find function of the Finder by no longer finding items in invisible folders
Comments
Re: Jaguar Update 10.2.2 No Longer Finds Songs
that was a bug, as it's been "improved" as listed here:
http://docs.info.apple.com/article.html?artnum=107140
# Improves the Find function of the Finder by no longer finding items in invisible folders
improve being a relative term i guess....