Lightroom 4 Lens Profiles
Adobe profide a lens profile downloading tool where you can search for a specific lens.
They also provide a lens profile creating tool which comes with detailed instructions. To create a lens profile you will have print out some suitably sized charts and take photos of them at different angles, apertures, zoom levels (if using a zoom lens) and load all the images into the creator for it do create a profile.
|Global Reach by cjf2|
|Maligne Lake by Pete of Oz|
from - Mountain Lake - (Full Colours only + A Border)