[Educated Guess]

Is there such a thing as a bookmark application for music?

I listen to a lot of mixes some of them 1-2 hours long and would like to bookmark certain songs and jump right back in.

My old Creative Zen had the option to bookmark and you could then select where you'd like to restart from a bookmark list.

[snaz]

Its not an elegant solution but if you change your tunes to audiobooks in iTunes then they will remember their position etc.

Its obviously not a solution if you actually have audiobooks for real, but if not it works. You keep their genres etc and they still work as normal in playlists too.

[Educated Guess]

Didn't know iTunes had that option. How do you change the tracks/albums to audio books?
Once you've done that do you choose to restart from a list if you have multiple bookmarks?

[muffins]

This might help

Lifehacker - Set your long MP3s to "remember playback position" - Digital Music

If you want this on all your music just select all right click on a song choose get info then options tab.

Then tick remember playback position and it will do this to all your selected music, click OK and you are done.