Rather than wait till someone gets you a URL where you can obtain WAVE songs from, I think you can go ahead creating these yourself. There are tons of tools on the web you could use for that.
Google for
'Audio Converters' for the conversion of your favourite MP3s and AACs into WAVE or WAV. JetAudio is a tight app for such functionalities and it's free. You can get it here:
http://www.cowonamerica.com/download/Next you need an audio cutter and joiner, which I think this might serve your purpose all too well...
http://www.sagasoft.net/download/mp3cutterjoiner.exe The essence of this is to cut the part of the song you want, the parts you want to use as your ringtone, or mere listening.
Take Care Man, and happy ripping, cutting, joining, converting your way into WAVEland.