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.
|Child and seal by APenza|
from Kids world
|Calatrava in Reggio Emilia by NCV|
from Your City - Telelens in the City
|Aurora's, Science and the Milky Way by man4mopar|
from My Best Photo of the Week