Thanks for the help guys.
I downloaded the try-before-you-buy version of Goldwave from
http://www.download.com/GoldWave/3000-2170_4-10754826.html?tag=lst-1It's perfect, but it's not free and I don't spend enough time on converting music files to make it worth it. If there is a free (or pretty cheap) package out there somewhere that does something similar to this then it would be great to get a copy of it.
I have just got here to have a look at your replies and I've just downloaded the SOX sound converter and I'll get back to you on how succesful I am with it.
OctaMED does allow you to load wav files but it tends to load up as just static. Aif seems to be the wrong format (it might be more appropriate for Apple software) and OctaMED much prefers IFF to anything else.
I'm after an easily searchable source of samples on the internet now, but that's something I'll have a bit of a look for myself before I bother you guys.
Cheers