First, what is an audio prayer? For those who don't know, an audio prayer is a prayer that comes via an audio channel. In other words, rather than having to read it, you can listen to it in a sound file format like you listen to a song or to an audio book. Common sound formats are MP3, WMA and others. Here are some sites where you can find audio prayers:
Pray As You Go - a site where you can download audio prayers in both MP3 and WMA format.
Prayer To Go - a site where you can listen to short audio prayers and read the words at the same time.
Audio Prayer Book -listen to or download prayers for morning, evening, families, etc.
And don't forget about YouTube. You can always convert YouTube videos to mp3 files using the software available online. I use the one from DVDVideoSoft.com.
Prayers on YouTube
Prayers in Songs
