Here is a lesson from disk 4 of Musicademy's Beginners Worship Keyboard Course. Its quite a complex lesson given that its on the Beginners set (showing some embellishments for added interest), so even if you've been playing a number of years, you should find something helpful here.
Hymns can be very daunting for the keyboard players. They always seem to have complicated chords and rapid chord changes. Here Tim Martin teaches a simple arrangement for How Great Thou Art (you can download the chord chart from the members area at http://www.musicademy.com/store).
If you do decide to buy the DVDs, you'll get another hymns lesson - Amazing Grace - as well as a play through of each song with the Musicademy band. There's lots on the DVD set besides these hymns, and even though this lesson might look a bit daunting for complete beginners, you will have gone through nearly 8 hours of basic teaching before you get to this point - probably the equivalent to a year of one to one lessons.