I realize this question has been on here for quite some time. More than likely, you've had your Question answered.
However - Many of the Songs / Hymns have Guitar Chords found above the Lyrics. These are Also Known As - Lyric/Chord Sheets. Most 'Church Praise & Worship Teams, usually use Lyric/Chord Sheets when doing Songs like this.
The Best place to start, when trying to tackle a Song like 'Amazing Grace' is to Learn how to play Guitar Chords. Guitar Chords is a Much Faster way of learning to Play the Guitar, compared to learning to Read Music.
If you want a Good Way of learning how to Play the Guitar Chords, that many Churches use when doing Praise & Worship Music - Check out - http://bgpfg.webs.com/
This website is 'Free Christian Guitar Lessons'. It's a pretty Cool website, with TONS of short cuts!