Best method of stopping mp3 hotlinking?

The myspaz flood continues

[wonderfulweb]

Hey guys, just wondering what the best method of stopping people hotlinking my domains MP3s is?

I'm guessing some form of Rewrite in htaccess?

I've read through a few examples of these here, but all that I saw were for slightly different situations, and I realize the rewrite code has to be exact or it can do strange things.

So, to return a 403 code to any other domain trying to serve hotlinked .mp3 files from my domain, how would you recommend I do this? I believe it will need to continue to serve mp3 files to domains/users with no referrer data to avoid damaging my own users experience?

Thank you for your help