Lightroom 3 has hidden the Chromatic Aberration feature.
Where is it you ask?
Well it’s behind the Manual tab under Lens Correction! Funny part is they forgot to include it in the Help section. And they abbreviated it to C. Aberration.
So, if you’re looking for the Chromatic Aberration correction tool in Lightroom 3 it’s under:
Lens Corrections > Manual > C. Aberration