Tony,

Thanks for your reply and suggestions. A music friend has suggested Transcribe!. It does lots more than allow slowing down the tempo without changing the pitch but it remains easy to use. Best of all it works with lots of sound file formats including MP3. It is shareware, available in Windows and MAC versions, and costs $40. I found the Transcribe! link to similar types of programs (The Competition) useful.

Thanks again for your help.

Michael