In wait of an firmware update of apple this trick solves the problem of gap between songs in them Cd mix of good enough way.

With the program xplay in the playlists or album of the cd mix to select the song click right button properties options
Select stop playback to remove 0.500 or 0.400 seconds of the time total.start playback deselect
Repeating the steps with all the songs with the last song is not necessary.

Examples:
4:44.850 after change 4:44.350
6:32.300 after change 6:31.800

I test with:
ipod 3G 2.0.1
Files mp3 128 kbps it is better. 192 failed some songs

xplay 15 day try xplay (http://www.mediafour.com/products/xplay/)