Adobe has made a second prerelease version of the Lens Profile Creator available in Adobe Labs. As you may know, the Adobe Lens Profile Creator is a utility designed to work with Photoshop CS5, Camera Raw and Lightroom that allows you to build custom profiles for lenses in your kit. These profiles “describe[] the types of optical aberrations that exist in a particular lens and prescribe[] how to correct the lens distortions in an image captured from the same lens.”
More details and download instructions over at Adobe Labs.