In case you haven't heard it elsewhere on the net, there are now subscription packs available for Civil 3D 2010. There are some pretty cool looking tools there (haven't had a chance to try them out yet myself). If you are on subscription, go to the subscription website and download it. If you aren't on subscription, then you'll have to wait until you upgrade to the next version or until you get back on subscription.
http://subscription.autodesk.com