Finding someone to host MP3s is difficult due to the Damn Motherfucking Crapeating Act (DMCA), it's too easy for providers to get in trouble nowadays just for certain files sitting around.
The BEST way to host files? Go check out Dreamhost or any of the other low-cost hosts. Often times you can get hosting with domain reg for about $7 a month if you pay for several months in advance.
Good deal.