From time to time I make attempts to memorize sections of the Heidelberg Catechism. I found a few free audio versions available below, as well as some files of the Westminster Confession of Faith.
Audio readings are often a great idea... poorly executed. That is, I've found many audio readings droning on and on, which leads to... boredom. Such is probably the case of some of the links below. Some may wonder how a catechism could be read in an exciting manner: "It's a catechism, not a dramatic presentation"! I would argue that something like Lord's Day 1 of the Heidelberg is filled with strong emotion, and could be read aloud with vigor for a recording. When I think about Lord's Day 1, I can hear someone like Alistair Begg reading it aloud with force.
I've not listened to all the links below, but my suspicion is the readings are flat. This means, it's the listeners responsibility to be as attentive and focused as possible to get the most out of it. Then again, some of you will probably listen to this sort of thing while driving, and I would rather you focus on the road.
URC Learning, The Three forms of Unity (includes the Belgic Confession and the Canons of Dort)
Audio Heidelberg Catechism
Heidelberg Catechism Audio Recording, Internet Archive
LibriVox recording of The Heidelberg Catechism
Heidelberg Catechism, Grace Reformed Church
And for you Presbyterians-
Reformed Audio Presents: The Westminster Confession of Faith
Sermon audio, Westminster Confession of Faith (1647) & the Solemn League and Covenant (1643)
The Westminster Confession of Faith, StillwaterRPC