This month's free audio download from ChristianAudio.com is Confessions of the Reformed Church (Unabridged), edited by David Cochran Heath.
It includes The Augsburg Confession, The Westminster Confession of Faith, and The Heidelberg Confession. These are three of the most significant Reformed confessions. For Reformed Baptists, of course, the Westminster is particularly important, since it is the confession used as the starting point for the Baptist Confession of 1689. But all three of these sources are useful for study and understanding the history of Lutheran (Augsburg Confession) and Reformed theology.