It has just occurred to me that if you are managing music to sync to the iPhone you should just be searching in iTunes instead. Import all the music into iTunes (being sure to tell it not to move the files). Then search in the iTunes UI.

This is exactly what I do to manually manage the music on my phone. However I don't actually use the "Manually manage music" option. I didn't find that worked too well. What I do instead is use smart playlists to determine what music gets synced to my phone.

When you add new music you can just ask iTunes to reimport the root folder for your music, it won't import duplicates.it