The blogger tutorial mentions several hosting services but I have not used any of the others so I have no opinion of them. I have only used Box.net to host audio once but I think it works pretty well. I have also used Podserve. Podserve is a service mainly used for podcasting but it makes the best single audio file server. Podserve is free! It may be easier to host the file on a server you control like a personal site provided by your Internet service provider but you should be careful if a file becomes very popular it could really rack up some fees.
More host: Xuploadz (Very fast, very easy!),