I used Mike Bellm... and it was wonderful. He will also sell you everything you need to do it yourself and you can even download a video online from him that shows you how to do it.
http://www.bellmtcs.com/
My original trigger was at a HORRIBLE 7.4 pounds not to mention it had a ton of creep. I requested a trigger down to 2# and it came back to me at 2.1# with ZERO creep. I got to tell you... it has made me a very good shot compared to before.