1. I have some DirectShow that can playback mp3s if you want that. It just works without anything else. But it's DirectShow... it works however and I used it for years for mp3 playback. It's in a nice and easy to use API.

2. If you have something that can decode the mp3, then you can just create a player using the framework code I sent you. Look at the ogg player class as a guide.