My personal view is that it's good publicity. I've bought a number of CDs as a result of hearing a track on Napster.

I've also decided against buying stuff after using napster to 'audition' it.

I'm not really sure why you feel discomfort at other people deciding what to with your music. Once you publish it, anyone can do what they wish. Radio has been doing that for 50 years, tapes and photocopying and other technologies more recently. Whatever people say, napster isn't qualitatively that different.

Be pleased that people like your music enough to want to share it. If it's good, you won't lose out.

Ed