Audacity.

why would you separate the tracks? Since you already have then in full lenght before u mixed them. Is it to create a mixcd with track-sellection perhaps? If thats the case, bad idea to split them and burn them. Every track will have a small pause, even when you chose 0sec gaps.

Not in iTunes with gapless playback enabled.

Well there are a lot of tracks where I dont like the 2nd or 3rd verses and just like the 1st one and the chorus of a song. Plus I like to skip around. Why would there still be a gab after choosing 0second gaps?

I use nero to burn CD's and on there I can chose to have 0 second gaps when burning and it has always worked just fine..

Its my experience when messing around thats you can hear a track jump to the next one. Depends how the cdplayer handles it perhaps, that little skip. I just make .cue files and import that into my burning-software, then the track stays in once piece and the software writes where the tracks begin and end. Much faster.

Could you explain this a little more? Or tell me where I could get more info on how to do it that way?

well, I've been thinking the last days how I did it last time and I just cant remember :s
But this tool seems to do the job cuemaster.org
You just insert every track from the mix, leave title/artis blank if you dont care about it and fill in the time where the track starts. Then save the cue file and use it in our favorite burn program. I use the free CDBurnerXP Pro, and just load the cue file, burn and have a nice demo cd that can be skipped, 100% gapless :)

Ok, thanks for the input!