Lightroom Journal, a blog from the Lightroom team, has new information from Tom Hogarty in Preview of Lens Correction Solution for Camera Raw 6 and Lightroom 3:
"Below is a preview of lens correction technology that will be included in Lightroom 3 and the Camera Raw 6 plug-in that's part of Photoshop CS5. This is an exciting development for our non-destructive editing technology and is designed to address lens correction via two methods: Lens Profiles and Manual Correction. The easiest application of lens correction is to apply the lens profile technology that encompasses geometric distortion(barrel and pincushion distortion), chromatic aberration and lens vignetting characteristics."
Read more... at the Lightroom blog. By the way, Photoshop CS5 will need to be updated after install for Camera Raw 6.1.
For more info, CS5 Help is live. Here's the preview of CR and LR lens correction along with a look at the Lens Correction tool in Photoshop CS5: