So onto part 2 of my little series of tanking and healing Halls of Reflection. We've now come to shaman healing.
If you've read my previous post, located here -> http://jinxedthought.blogspot.com/2010/01/healing-and-tanking-halls-of-reflection.html, you'll see some of the basic stuff to think about when healing HoR.
Healing - Shaman
Like I stated in my previous post, see above, I find it easier to heal HoR as priest than shammy. This could have something to do with the fact that my priest is quite better geared than my shammy of course, but also the shaman lacks some type of heals that are particularly useful in that instance, especially for the first event. But, the shammy also brings something that the priest doesn't - the cleansing totem. This means you can remove the curses and those awful poisons. If you've got a paladin for wisdom or a mage for some water (or your own water of course, but I'm greedy) you should definitely use cleansing totem and drink as soon as you get out of combat. If you don't have water or wisdom the mana will be very tight and maybe you'll need mana spring more than cleansing. But since you're a healer I assume you've got a huge stack of water ready for all occasions so cleansing totem it is.
Riptide is a really good spell and I always miss it when I'm healing on other chars. That and chain heal define shaman healing. You'll of course get plenty of use of your entire healing arsenal, as opposed to priests most other healing classes don't have that many different heals and usually have to use them all (druids have quite many too). Keep Earth Shield up on the tank all the time (duh) and keep Nature Swiftness close at hand in case someone, especially the tank, drops low. It will happen.
The really tricky part comes when you start fighting the first boss. Nevermind about tremor totem, as far as I've noticed his fear isn't removable in any way. After being feared and when everyone's down low you need to heal everyone up as fast as possible. As a priest this is easy, but as shaman you might have to think more carefully about it, since you don't have an aoe-heal which gives equal attention to everyone in the room. I usually go with Riptide on myself or the tank, followed by two Healing Waves on the one who are most low on hp. Riptide again and two more Healing Waves on the next two people. This should take about 10 sec depending on haste and should be enough before the next fear. You could also use Bloodlust/Heroism half way through him.
On the Run From Arthas-event there isn't much special to think about. There will be curses, which you can leave or decurse, depending on how busy you are. The curse does damage about equal to a half a lesser healing wave (depending on gear), so mana wise it doesn't matter if you cleanse it or heal it, unless you overheal. You can also shock the casters with Wind Shear to especially interrupt their Shadow Bolt Volley, which can hurt quite alot.
By the last wall (the fourth I think) using Bloodlust/Heroism is a good idea, if you're not still sated. I sometimes use Fire Elemental too, to help with some aoe damage. And that's about it.
Good luck on healing with your resto shaman!