I'm writing a larger project and a part of the project is playing MP3 files. Nothing fancy, just playing files from a playlist, start/stop, next/previous (can be done outside the library), fast forward/rewind. I'm looking for a (free) library, or any other method of doing that. Relying on an external player is not an option.
Bass Audio Library is one option.
Check out SDL.NET http://cs-sdl.sourceforge.net/ It's a library and has ways to play music.
NAudio is an open source .NET audio library that can play back WAV files, using ACM codecs installed on your computer for decompression purposes. It also has preliminary support for MP3 file playback (works good with CBR, not always so reliably with VBR). It can't do WMA and OGG yet though.