most burning programs will convert mp3 to cd format ... just select 'music cd' to convert them, and 'data cd' when you want them to stay mp3
(at least both 'adaptec easy cd creator' and '.....' damn forgot the name .... ah well .. those 2 programs are delivered with most of the cd burners)
another nice tool is 'cdex', which you can download for free (forgot where .. i have to do something about my memory
, but i think you can find it on google). with it you can easily make mp3 from your cd's as well as convert wav to mp3 and mp3 to wav