The 1650 Psalter

Charlotte PRC
—YouTube channel featuring congregational Psalm singing from the Charlotte Presbyterian Reformed Church (Charlotte, NC)

Christ Covenant Reformed Presbyterian Church (RPCGA)
—Congregational singing from The Comprehensive Psalter

Free Presbyterian Church of Scotland (Santa Fe, Texas)
—Congregational singing by the only U.S. congregation of the Free Presbyterian Church of Scotland

ScottishPsalter.com — Recordings
—A very comprehensive resource for audio files of Psalm singing from the Scottish Psalter, featuring several of the sites linked to on this page

Niallags
—Niall Maclennan offering both (1) self-harmonies (three-part), and (2) precenting for a congregation

North Uist and Grimsay Free Church of Scotland (Continuing)
—Midi files of recommended tunes for every Psalm

Performed in Heaven
—Congregational singing; also available as a CD by Christian Focus Publications

Presbyterian Reformed Church — Psalms CD
—Previously available as CDs for purchase, these ensemble selections are now available to listen to on the website, or as free downloads

Psalm Singing Online
—Different recordings for Psalm singing, the majority of which are taken from the Scottish Psalter (also featuring recordings from Sing Psalms and The Psalms for Singing: A 21st Century Edition)