I'm currently letting iTunes manage my music, which is something I've never trusted it to do.

I have about 8GB of music that's only on iTunes music folder and everytime I rip new CDs or download new songs I just put them in my Music folder, which I have added to my iTunes library - without copying it.

iTunes has already arranged that batch of 8GB of music into artist folders but I'm not letting it do the same with the new music I put on the Music folder. It's a bit of a nightmare, the music is all over the place and instead of being organised it's a mess. To top it all, the file names are sometimes wrong. For example, I ripped Amy Winehouse's Black to Black and the song name comes up as Amy Winehouse - Tears dry on their own, for example. So instead of the tag being Name of song: Tears dry on their own and Artist name: Amy Winehouse, it's all down as filename and name of song. Then in my iphone, when I wanna listen to the music, it's impossible to find.

On PC I used to use Media Monkey for this. I don't know what to do know to change all the file names and correct them. Help somebody!!

When you import songs into iTunes, it gives you preference options I think they are: [copy the file(s), move the file(s), let me organize my music folder]

When you let iTunes manage the music, it categorizes them into folders by artist and album.

Sometimes the digital signature of a CD gets mixed up with another (i.e., my brother's band has a CD that when you let iTunes import it and name the songs, it thinks it is an Iron Maiden CD from 1987). :)

There are a few different apps for OSX that you can use to fix your tags:

Fix Tunes : www.fixtunes.com
and one called

I Eat Brainz: http://musicbrainz.org/doc/IEatBrainz

I have used both, and both work well, however ... there are still some tags it cannot retrieve; mainly for Mp3s I ripped LONG LONG ago. :)