How can I convert dvf files to something Mac can read?

First, I couldn't find an obvious community to post this to.... sorry if this is the wrong one.

I have voice files that are .dvf files. I have them on my MAC because I moved them over from my old PC, but they won't play on the Mac. How can i easily convert them to something that can be played on the Mac?

I also tried moving them back to the PC via a memory card (because on the PC I have software that will convert to wav files) but the PC asks me to format the memory card, instead of letting me open it and move the files onto the PC.

Thanks for any suggestions.