I just want to double check:

Have always played it this way: You attack, you get the target lock, you can not use the target lock until the next attack/round of combat.

Is that right?...I'm looking at it and now im starting to wonder...I read the faqs but...seemed vague when it mentioned the 2nd attack. All i could think of was Corran. Just want to be sure.

You get the TL after you finish the attack.
Any way of getting a second attack in that round would be able to use that Target Lock.

Being Corran Horn, Having a Gunner, or Firing Cluster Missiles are the only ways at the moment.