You could take a look at Nightbringer's PvP build a few posts down, also Ice/Thermal, I wouldn't change much for PvE if anything. The heated argument that follows his post doesn't say much except "take Thaw it's good".
Hmmm....
Yes, I had a look but it's very short on offensive firepower to say the least, I was looking for a slightly more balanced build.
Also, isn't there a Res power, Pheonix something that I don't think was in that build and I thought might have been useful ?
Yeah, Rise of the Phoenix is THE combat rez. Resurrecting a fallen team member while damaging and stunning all the foes around you is quite awesome.
I have played an Ice/Thermal corruptor to 40 and I could give you some hints. The actual build depends on what you want to do with it... You WILL have not enough power slots, but the enhancement slots will be sufficient. So, just go ahead.
So, here is my to-do-list: 
- Get attack power. Ice Bolt, Ice Blast, Freeze Ray and Bitter Ice Blast work great, especially with Hasten. You will be dropping single targets fast and safe. Avoid Bitter Freeze Ray and Frost Breath. Ice Storm may be delayed to level 30 (see below).
- Get some support powers. The shields are great if you don´t mind being a buff-bot. People will see immediately that their shields have run out and many will complain as soon. Cauterize is nice, especially for duoing with a brute (something I have done for quite some time with great success on any difficulty setting and type of mission). Brutes and fellow corruptors will love Forge. Thaw is good for fellow corruptors and other aggro-drawing squishies (apply with foresight and don´t bother too much about it if there are no or almost no mezzing enemies).
- Get those late game debuffs. Heat Exhaustion helps your brute a lot against heavy-hitters like most Elite-Bosses and AVs. Melt Armour... well, you will want it mainly for yourself. Why? Look at the next point.
- Get the Blizzard-from-Hell. As Ice/Thermal you don´t have to stand in the midst of your targets to fire off a really nice nuke. Start off with Aim (after I7 anyway), then hit Melt Armour to debuff your targets´ res, follow up with Ice Storm (slotted three times for slow) and finish those poor wretches with your Blizzard. Nice way to make jaws drop while eliminating an orange-red threat without caring about that 16 target limit for "normal" nukes. 
Please don´t try this against enemies such as boss level werewolves. They just run out of the blizzard and beat the tar out of you. Other wolves are fine (and dead).
If it has eyes, you can blind it, if it has blood, you can make it bleed, if it has a mouth, you can make it scream.
After looking at the actual build you're right, it's very team buff oriented at the expense of attacks. All of Sin's advice looks good. There are some lame ducks in Ice but pretty much all of Thermal is good.
Thnaks for the help
Hi.
I've started and Ice/Thermal build based around the concept of a Battlesuit that uses the laws of Thermodynamics.
Anyway, I've levellled up the first few, have fire and plasma shield, thaw and cauterize and a couple of attacks but I'm not sure where to take it.
Does anyone have a good build for Ice/Thermal with a view to being a team player?
Thanks in advance for any assistance.