Leveling Warlock Spec Needed

I am leveling this new group which consist of a pally tank, shaman, mage, lock, and priest healer. I have not played warlock in years and I am wondering if someone can suggest a spec for me. My guys just dinged 40 tonight. I tried using the search feature for warlock spec but didnt have much luck sorting through all the post. Right now I have been dumping points in destruction and using curse of elements, corruption, immolate, spam shadow bolts. It seems to be working for now but as I get higher in levels I will need to decide how to spec this guy better.

I would level affliction, then change to Demo when you get FelGuard. Level 80 has been discussed all over the forem, so this IMO,YMMV

I am running 5 warlocks at the moment with demo spec. So far instancing is trivial with 5 voidwalkers tanking. They are lvl 49 at the moment.

If you run a single warlock in a mixed group then go either affliction or destruction. Spec demonology up to soul link with improved voidwalker, so your pet can offtank when needed.

Then it depends on your total group dps. If you have low dps and things die slow, then go affliction. Otherwise go destruction because affliction needs some time to build dps. On long fights practically all warlock builds are the same DPS wise.

Pros with affliction: You are very unlikely to get aggro because your DPS builds slow but steady. If you get aggro you can just drain life and survive in most cases.
Cons with affliction: if the group has high dps by the time you lay all your dots on a target it will be dead and your dps will be low on trash.

Pros with destro: you are just a shadow + fire mage with pet and have lots of dd potential. If you have mages in group, it's a good combo.
Cons: if you draw aggro and you have no soul link you are more like dead. There is huge aggro chance because your main nuke (shadow bolt) hits really hard at low levels.

Pros with demo: your voidwalker can offtank and your survivability is good... more or less comparable to a mail armor class. Excelent choice if your tank tends to lose aggro or you need offtanking.
Cons with demo: lower DPS at lower levels until you get the big demo talents or spec for extra DPS in other three.

Until level 44 I'd probably do something like this: http://www.wowhead.com/?talent#IZZE0GVbcuVo:br

Then put the next 2 points in aftermath. From there head towards: http://www.wowhead.com/?talent#IZcr0...GVdcuVsAfct:br

Or at 50 you can go Demo to get the felguard with something like this: http://www.wowhead.com/?talent#IZ0GfhkAbi0sLz:br

your warlock is always going to trail in the DPS numbers because all of his spells take time to ramp up, shadow bolt casts slower than your other characters main spells. Warlocks shine on the long fight and your not going to find many of them.

Since your in a mixed group I suggest destruction, it's easy to setup a click macros for his spells and there are fewer DoT being wasted on short fights.

Warlocks are awesome to level. Is your main XP from questing or from instances? I ask because going demo enough for the Succy to have decent DPS (until 50) gives you an excellent option for multi-kill fun. The trick for me was to DoT something, send the pet at it, and then ignore it while I fought something else. This basically means that your warlock+pet are soloing 1 mob while yout team is working on another. After you get to 50, get the felguard and from then on put everything into Demo.

It's a warlock. It really doesn't matter unless you're solo.

I'd pretty much agree with Alcattle.
Affliction is by far the most mana efficient, especially when leveling.
Which means the least down time.
Although, with 5 toons each only expends roughly 20% of their one-boxed resources per pull.
So it probably won't make a huge difference any spec.

If you have a spec in mind, for once the team is 80th across the board.
I'd probably go with that one.
Just so you can set up your hotkey for Shadowfury or instant cast Howl of Terror, and learn it as you go.

If you don't have a spec in mind.
Affliction till 50th.
Felguard at 50th, eventually building towards Ruin in Destruction.
Ending at 0/50/21, at 80th unless you have a different spec in mind.