Mp3 blogs have been around for over 3 years now and I don't think a single one has ever been shut down for legal reasons.
For permanent track hosting, I suggest divshare.com
The only catch is you have to sign up (takes a minute). However, your files do not expire and people can download them without restriction. The site also allows for direct streaming of the material on your site.
Another option is sharebee.com
Your files are mirrored on 4 separate hosters but may eventually expire