The True Strike spell negates the miss chance from concealment.
Usually you cannot sneak attack on enemies with concealment.
Does negating the miss chance mean they do not have concealment?
What about total concealment? Does the spell also allow you to sneak attack a creature under total concealment (for example total darkness) provided you know where to aim to?
The spell true strike (and, likewise, the magic weapon special ability seeking) doesn't, upon launching an attack, grant a flash of insight that also allows, for example, seeing through darkness, detecting an invisible creatures, or a temporary respite from blindness. Even on an attack made with the benefit of the spell true strike, a foe with concealment relative to the attacker remains concealed from that attacker. Even if the attacker knows one or more squares a concealed foe occupies, sneak attack says, "The [attacker] must be able to see the target well enough to pick out a vital spot," and the attacker can't do that if the target has concealment.
The spell true strike removes the miss chance from concealment but not the other benefits of concealment, and one of those other benefits is that concealment often prevents precision damage.
The wording of True Strike is:
You gain temporary, intuitive insight into the immediate future during your next attack. [...] Additionally, you are not affected by the miss chance that applies to attackers trying to strike a concealed target.
The wording of Sneak Attack is:
The rogue must be able to see the target well enough to pick out a vital spot and must be able to reach such a spot. A rogue cannot sneak attack while striking a creature with concealment.
By a strict reading, the target still has concealment, even though you are not affected by the miss chance. And you can't see the target any better, you just have insight to guide your attack.
On the other hand, your insight is good enough to give you a +20 to your attack and bypass miss chance from concealment, this should be good enough to let you "pick out a vital spot".
As a GM, I would lean towards allowing it.
