How should I prepare a carbon frame when I want to swap in a new bottom bracket? My four-year-old, carbon-framed road bike has developed a case of creaky cranks.

I only hear creaking when pedalling hard, when I pedal more softly it just sounds like it has always done.

Given the bike's age it just seems like a good idea to replace the bottom bracket. But I was wondering, once I get the old bb out, how best to prep the frame before fitting the new bb? 

I've only changed BBs on steel frames before, where I applied some pretty thick grease quite liberally around the shell. But is approach applicable to carbon?

Some supplementary info: I'm riding a 2010 Giant TCR Advanced 2, with a 6700 Ultegra groupset, including hollowtech 2 cranks. I believe from the bike's spec that the bb involved is a press-fit bb, as shown on the Wiggle site. Having said that I've not taken anything off yet so this is all theoretical so far - I'm going to visit my LBS later today to get the relevant preload cap removal tool, so I can have a bit of a look around.
If it is a press fit then it is probably a BB86.  You'll need a removal tool (Park BBT-90.3, I think) and a press.  Get a SRAM GXP press fit bottom bracket or the equivalent Shimano part, they run about $40 USD. Knock the old one out with the removal tool and a hammer, clean the inside of the shell and press in the new one.  No grease.  The shells of these bottom brackets are made of a very hard plastic that will eventually loosen and start to creak.