I have a package called Adobe Album 2.0 which has several pretty good calendar templates, easy to use and quite effective. I have used this for several years to make calendars.
Unfortunately, Album has been discontinued, but Adobe suggests that most of its features are in the current version of Photoshop Elements (and certainly not in full-blown Photoshop). Adobe's website is a bit vague on just what Elements 6 will do, but you can download a 30-day free trial to see if it does calendars.
If all else fails, Bill's techniques sounds pretty straightforward.