Well, my fourth alt was a shaman and, while I did level as elemental, I also made him a healer and used a healing spec through the dungeons. As usual, this is all purely theoretical, so don't crucify me if I'm wrong, just let me know and I'll try and fix it.
Talents are... let's just say a bit weird. I'm really not sure what you should do with some of them so allot of this is probably personal preference. I guess 31/2/3 is what I would go with right now, but only it's hard to tell what will soon be preferable. Depending on your mana and output, you might instead put 3 points in Improved Shields and two points in Acuity. If you really lack mana, you could even remove Acuity completely and take Telluric Currents instead. It really is completely dependent on your gear and preferences. Also, the one point in Cleanse Spirit could be put somewhere else, but I figured, if I need to cleanse him, he is probably taking damage. Basically, give it some thought and redistribute as you feel is needed.
This is a bit easier to chose, but there's still some options left. For prime Glyphs, you should probably go with Earth and Water Shield. As for the third one, both Earthliving Weapon and Riptide are viable, but Earthliving Weapon more so. You could also go for Shocking if you feel that using Shocks is taking to much of your healing time.
Major glyphs are pretty straightforward. Take Chain Heal, Healing Wave and Healing Stream Totem. It will give you some flexibility and improve your performance.
For minor glyphs, this is really completely your choice, but I will probably take Astral Recall, Renewed Life and Water Breathing, simply for the convenience.
Gear, Reforging, Gemming, Enchanting
First of all, you will be using mail now. Sorry to say, but if you had cloth and leather pieces, you will need to find some replacements as the 5% bonus is good.
Other than that, the gemming will remain the same except SP is replaced with Intellect. You will probably be using the Frost relic from now on, as relics don't give you special procs anymore and are simple gear items instead.
You will probably be able to keep your old enchants without much issues, but you could get Brilliant Spellthread, Arcanum of Blissful Mending and Greater Inscription of the Crag now.
As for reforging, there are no caps to reach, but do try and track your haste levels to see when you can reach certain thresholds and reforge accordingly.
OK, we are out of DPS and Tanking waters so I rally can't help to much here. There is no "rotation" or priority system to follow. Heal as needed and pick the right heals for the right situation. Don't waste mana and be smart. All that I can say based on the news is that you will be shocking allot and maybe electrocuting if you picked the talent.
Well, I believe this would be it for my shaman guide. As I said, healing requires me to test things out, so I really can't decide on allot of things based just on numbers. You will have to change the way how you heal, that's for sure, and in this case, the best tip I can give is to practice.