I just installed a set of Crimson Trace Laser Grips model LG-401-P1-Custom, in Burlwood Finish with Front Activation on my Kimber 1911. They are very comfortable and work really well.
If you have a Ambidextrous-safety model 1911, it requires you shorten your right safety - my gunsmith charged me $20 and did a very professional job - a friend of mine did his own shortening using a "dremmel" and was very careful to well protect his 1911.
These are available from Crimson Trace, but cheaper from other websites, just "Google" Crimson Trace Laser Grips model LG-401-P1.
you might want to take a look at the vz alien grips, they're the best grips i've used on a 1911. seriously grippy without tearing up your hands. just a great design. made from g10 material, i just ordered my second pair.