There is this priest trial in my guild right now. He applied as a discipline priest but what we were looking for at the time was a holy priest. Unfortunately, he doesn't know how to play holy, so I'm exploiting my veteran status and making him learn it. Coincidentally, the big bosses also want all of us here at WoW.com to work on these 101 columns, so this kills two anything-but-birds with one stone. I really like birds, by the way.
The following is meant to be an introductory guide to the priest holy tree. It is not going to tell you what to do step by step (at least not until you get to the enchants section) instead it intends to show you some options from which you can get started. If you're already a veteran holy priest, feel free to add anything I left out in the comments so readers who use this column as a resource can get as much help as possible.