searching for MP3 files

If you could explain what exactly is "different locations." Mine are organized into folders by Artist name and Album name.

The files, as opposed the the actual music, are named however they are imported. Mine were imported with a prepended track number based on the original album track ordering. I'm not sure what iTunes does, now.

To search for them, set your Finder Search preferences to "Search current Folder," then open you home folder and type Audio into the search field. Select Kind is Audio.

All of your audio files will show up in the search results.

If you just want mp3, then you can choose that search token.

iTunes maintains its own metadata separate from the id3 tags. Your truck can only process the id3 tags, not the iTunes metadata.

If you want all of that info passed on when you export, you need to update the id3 tags for each song (Get Info). There are apps that can do this automatically, but I don't know how useful/safe they are as I've never used them.

Physical file locations on disk are taken care of by the operating system. You don’t need to know where. (Same in windoze.)

You can find any file by name in search (spotlight).

The files will stay in whatever folders you saved them.

You can add them to your music library in iTunes (File, Add to Library) and the originals can be deleted if necessary,

You may also be confusing iTunes with Photos, Aperture and similar apps which will store your pics in a random unreadable fashion within the Library.

itunes will always store your mp3s or m4as in recognisable folders under thr itunes music folder according to artist (generally)

in both cases, however, you search for music or photos in the iTunes or Photos app.

So what you meant is some songs are in the wrong album or no album? Usually caused by copying from windows or other sources. Even CDs have incorrect song info.

As mentioned above, in iTunes you need to click on an album and select all the songs. Right click and then select Get info. Note the values in each field (i use screenprint) . Then find the rogue song, right click and select Song info. Change the fields to EXACTLY match the album but change track number to the right value. Its a painful long job. You can then export to a stick or play in a car and the album should be intact.

You could come back and explain how they got scattered around.

Are these mp3 files in your iTunes library? You can Control (right) - click on a track and select Show in Finder to see where the source file is located.

In iTunes' Advanced preferences pane make sure these two checkboxes are checked:

That will help consolidate your media files in the library.