I think the simplest solution is to store mp3 in your apache www/mp3 directory and then use a web index like this:
http://larsjung.de/h5ai/
The "problem" is that you will need to download the entire mp3 since it has no streaming option out of the box.
If you know a bit of php/html5 maybe you can develop a streaming function
I can suggest you: http://www.schillmania.com/projects/soundmanager2/
I also suggest you to use Nginx since you have to deal with static content it is lightweight and faster than Apache, expecially on the Raspberry Pi!