When James Grant spoke on introducing your church to Psalm singing last week he handed out a very helpful little booklet. He has now posted the booklet. In this post he links to the booklet and lists some other resources.
This booklet is great. It gives a basic overview of meter and lists some commonly known hymn tunes in some of the most common meters. With such a list in hand you can pick up a standard psalter and begin singing Psalms.