This is a list of my favorite WoW priest-specific and general healing guides! If you want me to add a link, message me :D More will be added over time. Have a favorite link you'd like to submit? Feel free to suggest it on the blog or at the Facebook page!
General Healing Links
A Beginner's Guide to Priest Healing
http://www.blizzardguides.com/wow_priest_healing.html
While it initially SOUNDS Priest-specific, a good portion of the information is relevant to ALL new healers, regardless of class, so I put it in both link lists.
WoW Insider
http://wow.joystiq.com/
This is a massive, compliation-blog of virtually everything there is to know about WoW. It's a fantasitc site for just about anything you need to know about the game. :)
Healing Guide, WoW Insider
http://wow.joystiq.com/tag/healing-guide/
A healer-specific compilation of WoW Insider's blogs, for easier access.
The Healer's Guide to World of Warcraft, Ten Ton Hammer
http://www.tentonhammer.com/wow/guides/general/healing-guide
A nice, basic guide that links off to the different healing classes' pages for more in-depth info. Good for beginning healers.
The Best of the Best Healing Guide for World of Warcraft
http://www.associatedcontent.com/article/1371956/the_best_of_the_best_healing_guide.html?cat=19
A little outdated, but still has relevant info for all healing classes.
Druid-Specific Links
Jiyambi's Guide to Tree Healing, World of Warcraft Pro
http://wow-pro.com/wowpro_archive/druidresto_jiyambi039s_guide_tree_healing
This has EVERYTHING you'll ever need, from spell break downs, to talent builds, to glyphs, to gear lists. Definitely a nice site. It is, however, a few years old so things might have changed, but it's still worth checking out.
Resto 85 Healing in 4.0.6 (Cata expansion)
http://www.restokin.com/resto-druid-healing-guide/
Another one-stop-shop site, this covers almost everything you'd need to know for healing as a Druid. They also list some links to other Druid Healing posts and sites, which was really cool.
Druid Guide, Ten Ton Hammer
http://www.tentonhammer.com/node/26256
Of COURSE I'd list TTH as a link, they're really useful. What else can I say? Go check them out.
Shifting Perspectives, Joystiq
http://wow.joystiq.com/category/shifting-perspectives/
Joystiq holds many fantastic blogs for WoW, and Shifting Perspectives is no exception! They post weekly on various issues concerning Druids. Much love to Joystiq.
Paladin-Specific Links
The Holy Paladin Guide for WotLK, The Elitist Jerks
http://elitistjerks.com/f76/t35975-holy_paladin_guide_wotlk/
Despite the fact that many game mechanics were changed in Cata and Paladins were basically nuked to hell, this is still a FANTASTIC guide and deserves to be looked at.
Concise Holy Paladin Guide, WoW Contender
http://www.wowcontender.com/blog/paladin/holy-paladins-in-4-0-3/
Covers the changes that Cata made for Paladins and then what to do about them for healing. Good place to go to.
Healing Cataclysm Holy Paladin Guide, Tankspot
http://www.tankspot.com/showthread.php?63314-Cataclysm-Holy-Paladin-Guide
A REALLY thorough series of forum posts that go into every detail needed to learn how to heal with pallys. I thoroughly approve.
Priest-Specific Links
WoW Priest
http://www.wow-priest.info/
What can I say? Fantastic site with virtually EVERYTHING you need to know about Priests. Ever.
WotLK Healing Compendium 3.0
http://elitistjerks.com/f77/t35208-wotlk_healing_compendium_v3_0_%5Btheorycraft_specs_etc%5D/
An EXCELLENT forum post about healing priests and raids, covering EVERYTHING you'd EVER consider for raiding.
A Beginner's Guide to Priest Healing
http://www.blizzardguides.com/wow_priest_healing.html
While it initially SOUNDS Priest-specific, a good portion of the information is relevant to ALL new healers, regardless of class, so I put it in both link lists.
Spiritual Guidance, WoW Insider
http://wow.joystiq.com/category/priest/
I linked to WoW Insider for general healers, but Spiritual Guidance is another blog for specifically priests and is my go-to for a lot of things. Definitely worth checking out :D
Holy Priest PvE Starter Healing Guide (For 3.3)
http://missmedicina.blogspot.com/2009/09/holy-priest-pve-starter-healing-guide.html
This is a good, effective guide. Covers talents, spells, stats, glyphs, rotations/strategies/tips for single-target and group heals for 5-mans and raids and also discusses possibilities from Discipline and Shadow trees for certain sections. There are separate posts for gems and enchants respectively.