Civil 3D 2007 service pack 3 is now available. Be sure to look at the readme file.
You will most likely need Land Desktop Companion SP2 and Civil Design Companion SP2 also.
All three service packs can be found on the Civil 3D Updates and Service Packs page.
DO NOT install the Land Desktop service pack from the Land Desktop Updates and Service Packs page if you have Civil 3D.