I've had some creaking problems as of late and have done several things to remedy it.
Bike: Scott CR1 Team Issue, `07 Campy Record compact group, 11-23 cassette, FSA K-Force Stem and bars, Ritchey WCS Carbon Seatpost, Specialized Toupe Saddle, Campy Zonda wheelset, Look Keo carbon pedals.
Here is what I have done:
Eliminated seat post as it does not creak when out of the saddle.
Made sure everything was tightened and lubed including skewers, pedals, cables, bearing caps, etc. Even put a little lube on the dropouts as well.
I lubed and cleaned the chain. The bike sounds perfect for the first 20-25 miles and then it starts to creak. A little at first, only noticble when the bike is loaded up, but then by mile 40 it creaks when spinning. It gets embarrassingly LOUD!!
Checked for chain, chain ring and cassette wear, and all is fine.
This happens weather I do the ultra anal chain clean where I lube each link individually, wipe excess off meticulously, and use cue tip to wipe the inside of the chain, then repeat. Or when I do the quick and dirty lube and wipe. The lube and wipe eliminates the creaking for the next ride, but after 20 miles or so it comes back. I use Pro Link chain lube. For the greased parts I use Finish Line Teflon.
I ride in socal so the roads are not any more dusty and dirty than the average road. I would actually rate the road above average for cleaniness.
Brought it to a reputable LBS and they put lube on the dropouts. That helped int he parking lot, but I think this is a new creaking issue.