In Cool Edit, you're looking for a "convert" option from the edit menu (I think... it's been a while!).
What you should find is an option to convert from Stereo to Mono, and in that it'll ask you if you want to discard one channel or mix the two channels.
Discard the left channel, do a "Save As" as right.wav, then
Discard the right channel, do a "Save As" as left.wav.
bingo - two mono files.
if you get totally stuck, post again and I'll re-load Cool Edit and find the exact sequence of commands for you.
- housepig