>We have a zillion WAV files that have both voice converstation and DTMF tones in it. Obviously, WAV files are not the smallest sound files - so I'd like to convert the WAV files to some other format. I haven't messed with it much, the problem is the gizmo I use to pull the DTMF tones out of the audio files seems to fail when I convert (compress) the WAV files.
>Anyone have any sugestions on a CODEC I should try that will keep my DTMF tones?

Have you tried converting the WAV files to MP3? I think you might have a hard time compressing the WAV files and keep the DTMF tones. Compression usually means some type of loss of information. If I recall correctly DTMF tones are sine waves and your "gizmo" is probably pretty sensitive i.e. high sampling rate.

Do you have any specs for your "gizmo"?