Use TMPGEnc with the QTReader and save the WAV file and then do what you want with the WAV (you might also be able, you should rather, to save as MP3 or what not)
If you have a mac I know this works. It may work with the PC version of iTunes but I don't know for sure. Here is what you do with the mac. find the mov file that you want to extract the audio from and drag the icon of the mov into the library song list pane of iTunes. iTunes will automatically rip the audio into the iTunes library. From there you can use iTunes and convert the audio into mp3 or AAC or burn it to a cd that will play in your car. Also if you have Quicktime Pro you can simply go file to export and then choose the setting for Audio to Wave or any of the other settings and export it out. Hope this helps.