I have an older Dean Ti bike with a carbon fork and Mavic Cosmic Elite wheels that does the same thing and it's the plastic end caps on the hub. Whenever it starts up I take off the end caps, clean everything, apply a little grease to the contact surfaces and then re-tighten the end caps and axle. It'll stay quiet for a few hundred miles before starting up again and I just repeat the service process. The same thing happened on one of our tandems which had a True Temper Alpha Q AX fork and Phil Wood hubs. The noise was coming from one of the cartridge bearings. I just popped out the bearing, cleaned everything and applied some Loctite 242 (blue) to the race and pressed the bearing back in; problem solved.
Not sure if this is what you're dealing with, but it's easy to check: just grab a hold of the front wheel and apply pressure on it back and forth from side-to-side. If you hear creaking it's either the fork drop-outs or the hub. If you have a spare wheel, put it on the bike and see if that stops the creak. If it does, it's your hub. If it's still there, it's probably a fork drop-out.
True Temper will replace loose or damaged drop-outs in their carbon forks for $25 (or for nada if covered under warranty, i.e., you didn't drop the bike on the fork ends or crash it) and turn-around is just about a day or two + shipping time; I would suspect Reynolds, Bontrager/Trek, and other folks who still fab and/or service their products in the US would offer a similar service.
Just some things to look at.
Last edited by livngood; 09-09-04 at 08:49 PM.