What application can play the DAT files for you?
A ".dat" file is typically a data file created by some software for archiving...
Maybe the files are already WAV files or some other format but they have been named with the extension ".dat" perhaps?
If you could upload one of these DAT files or link to where you got the files from that might help us in helping you more.
If I can play the file here I'll be able to tell you fairly instantaneously what codec/format it uses, what is necessary and how you could go about converting it.