I have a phone service that sends me emails of voicemails in .wav files as attachments. How do I get them to play on my iPhone 4 (and 3GS)?
Taking a wild guess as I have never had to play audio files not compatible on my phone but try getting an external app that could possibly read it such as Dropbox and in the message, tap open with -> dropbox.
If that doesn't work, its in your dropbox so you could open it on another device that can play .wav files.
Hope this helps!