So my last iphone 4 was messed up somehow -sent it in - now have a new one.
Last iphone 4 was version 4.0.2 - jailbroken, unlocked & used with tmobile just fine.

NOW, my new iphone is version 4.2.1 BB 03.10.01 when they sent it to me.
I'm having trouble finding the carrier unlock for this. I figured it would be out already but can't seem to find it anywhere. I can only find old (dec 2010) posts about how it's coming out but by now (feb 2011) it should be out.

Does anyone know where I can find it? Please, please, please help!

Currently my iphone is jailbroken with greenpois0n RC 6.
Does my iphone 4 need to be jailbroken with a certain jailbreak to be unlocked?

There is no unlock yet for this baseband. Wait until iOS 4.3 is released, when it is released we might have a clearer picture regarding unlock.

If you had actually searched properly you would have found this: Twitter - we have referred to this tweet from the iPhone Dev Team many times.

Just wait (like everyone else who is waiting for an iPhone 4 unlock) patiently and please don't create duplicate threads asking the same question we have answered 100s of times already.

When the updated unlock is released, there WILL be a thread for it under the ultrasn0w section of the forum. As long as there is no thread, you can assume it hasn't been released yet.

Thread closed.