xmms-crossfade is an output plugin for XMMS. Its main feature is automatic crossfading. It also removes the gaps between tracks, to play whole MP3 albums without any audible interruption. xmms-crossfade supports OSS via a builtin driver, and any other platform by using existing output plugins. As of version 0.3.9, the Audacious media player is also supported.
Just the right thing!
When looking for a streamlined and easy-to-use audio resampling library to use in your project, you just found it!
Resampling can be done either on a single block of audio data at once or, for streaming purposes, in smaller chunks of data, while libsamplerate takes care of managing the state.
After playing around with other sound daemons, I finally found what I wanted: A very well done, low-latency (as promised), feature-rich and easy-to-use program.