First off you can buy inscriptions on the AH for your class. Just go the the "glyphs" tab and then your class. For PvE I reccomend the water shield one, mana tide one, and chain heal one.
For level 80 reg instances you should have around 1100 SP before EL weapon. As far as heroic go, I feel that they are a much bigger step up then they were in BC. Mix in the fact that most of the people you'll be grouped with will have lesser gear then your used to and they can get really tough. I have just over 1600 SP and 350 MP5 unbuffed and without EL weapon, and I've still had to bail on some heroic because we couldn't cut it. I'd say atleast 1400 MIN before you go into heroics.
Grab the Wyrmrest tabard and get your rep up with them so you can get the mace. Run alot of reg instances (lvl 80 ones) to work on your rep and pick up more gear.
Once you can heal heroics you can heal naxx. Depending on the progression of your server you may not want to pug it though. People seem to think that because they did it pre TBC that they can do it undergeared now. It's still pretty tough but with it's set up you can hit up alot of bosses while skipping some. There's lots of good gear in there for shams that are massive upgrades.
Also, if you have the gold, the new LW mail peices are really nice to start out with. You can pick up them in the AH for pretty cheap due the the mats being pretty cheap. It's a good place to pick up a helm and shoulders.
I actually use riptide alot while healing. In some situations with a good tank earth shield and a few riptides is all you need to keep them topped off during a pull. It's also a good instant heal to toss on a ranged DPS that took some aoe damage or yourself if you do. That will allow you to top yourself off without wasting cast time on the tank.
I'll also use it on the tank right before he runs into a fight for the chain heal buff if I know he's going to take heavy damage from the start. You just have to be creative with it and it becomes pretty useful.
And as always remember to have water, mana pots, health pots, and maybe some stat food with you. I also always have a mojo elixir and a frost wyrm elixir on me just incase.
Edited, Dec 5th 2008 5:08am by DarkHybridX