Well, wait... what do you want to do with this MP3 DVD? If you want to play it in a DVD player or MP3 CD player, it won't work most likely. Most DVD players do not recognize MP3s on a DVD the same way as an MP3 CD.
If you want to burn a bunch of tunes, just use iTunes. Go into the Burning prefs and set it to Data DVD. Then pop in a DVD and hit Burn 🙂
In Toast, if you want to burn MP3s onto a DVD, use Data (Mac & PC).