Hi Larry,
correct what Bill says, type behind asf files f.i. tutorial and you find info enought.
To be short: MP3-songs have become wellknown formats. For using it as e.g. background in a website it is still to large. ASF-files can be seen as a compressed MP3 file (max. of 400/500 kb) which is usable over the internet. It is streaming format, which means that one must be 'on line' to hear the song playing.
For making WAV files to MP3 and MP3 to WMA/ASF is encoder software free available on internet.
Greetings,
Cees