http://wotlk.openwow.com/?talent#bxc...cboZMxthbbVbZh
Start with 3/3 Spirit Tap, then move to Holy until Surge of Light, then fill up the remaining points in Discipline. Glyphs: Smite & Inner Fire. Your Smite and Holy Fire hit like a truck, you have mail-like armor with glyph of inner fire and plate-like armor after you get Improved Inner Fire. Reflective Shield adds up even more damage, Power Infusion turns you into a Smite machine gun, and if you ever get into trouble - Desperate Prayer, Blessed Recovery and Martyrdom will take care of everything. Whatever you do, remember the most important thing - stack Spirit like it's the only stat in the game. Usually you'll end up having more spell power than a leveling shadow priest...
You're welcome.