Will I be able to play a healer?

Will I be able to spec my character to be completely support and heal my allies?

Or does everyone have to have a combat role?

I didn't see any heal abilities when I scanned the skill gems but I am not sure...

There are no direct heal abilities, but there are a few options:
-Rejuvenation Totem http://www.pathofexile.com/forum/view-thread/30762
-Vitality (an aura) http://www.pathofexile.com/forum/view-thread/22682

You could put on some more auras to support your party even more (e.g. Purity (ele. resistances), anger (added fire damage) etc.) -> don't forget some passives to increase their radius

EDIT: also maybe doing some specialising in spell crits and going cold damage (crit. hits with cold daage freeze the enemys, and even if you don't freeze them they are still slowed at least).
Ice wall might also be worth considering as a 'supporter'

EDIT2: also there is a passive keystone which allows you to share your charges with party members (its called Conduit)

EDIT3: and curses might also be an interesting choise for a more support orientated character

There isn't any direct healing abilities, but you could potentially focus completely on support with the various auras and curses, and perhaps skills such as ice wall and bear trap. How well that would work out is another question entirely...

The thing is you can run a few auras and curses and still attack stuff, so you might as well :P

Edit: My post comes across a lot more discouraging than I intended. It would be interesting to see how effective a purely supportive character would be. The previous poster has given you a good run down of skills and passives to look into :)

I kinda like the idea and did some theorycrafting:
Link

I don't know if this would be the best possible support build, but i think it should at least be worth a try ;)

EDIT: if more defensive nodes would be needed you could easily drop the cold damage passives and the chill duration as well... but as i said in my previous post i kinda like cold damage as a support element ;)

EDIT2: (yes i love to edit my posts :P) i changed the build a bit:
Link2
Dropping the health nodes (and a few other ones as well) and going for Chaos inoculation and some energy shield passives.

Also I know that we get the new passive tree soon, but i couldn't resist doing this ;)

What possibility do you think there is that they add more abilities prior to OB?

I think it would be a good idea to open up field with options to create custom classes that fill a niche like healing, or primarily CC. (allow for more CC abilities?)

Thing is the game isn't really based on the old MMO trinity: healer/tank/dps.

And the auras themselves do not require expensive specialization that would justify them being more powerful than they are atm.

So the support role would be more something to enjoy with close friends, imho.

Exactly.

My friends and I want to make a team to play together. While it is still possible, I would like to have it more severely divided.

Yeah

tanker-endurance charge(must shape, 98 points)

Ya want some charges?+possible discharge(111 fantabuild- to shape)

The CCmastah(an other useless 111 fantabuild to shape- just what you strived for, raigt?

If you wan't to build a team that relies on others, while you can't do full-on healer, you could do more of a support role that focuses on the Auras. Some players being pure-Tank with minimal DPS, being supported by glass-cannons for pure damage, and then someone running with a focus on auras.