EWTN. Huge archive of audio programs from the Eternal Word Television Network. [RealAudio only]
Peter Kreeft. Several recorded lectures from popular Catholic author Peter Kreeft.
Pontifical Institute of Sacred Music. A selection of sacred and classical music in MP3 played by teachers and students of Pontifical Institute of Sacred Music.
Soul Amp. Catholic contemporary music project, offering free MP3s of songs inspired by the New American Bible, the Catechism of the Catholic Church and Catholic teaching.