I'm probably going against the grain here - but I think I did a form of CC when ds was very young - like less than 6/7 weeks old. I didn't know anything about CC at the time (wasn't on mumsnet then!) but when putting him down for the night I'd leave him to fuss for a wee bit, often standing outside the door and timing before going into him, reassuring and settling him and then going out again. After a few nights of this he really settled into a sleep routine and has continued to be a great sleeper.
I really wanted to say that I think there's a big difference between crying because they want something (food, heat, comfort, a new nappy) and general fussing before going to sleep. I wouldn't leave ds to 'cry it out' if I hear a certain type of cry, even now when he's nearly 11 months. However, for us doing what we did really worked - as I said at the time I hadn't read much and was making decision based on what I did know - that babies need sleep, that getting into sensible routines helps and that I also needed my sleep. I've since read a fair bit of the research, and I am convinced that emotional damage can be done by leaving babies to cry - for a while I worried that I'd damaged ds.
However while he's probably too young to really show much, the evidence in terms of his behaviour etc is that he's fine - better than fine: a really happy child. Obviously his happiness and contentment is in a broader context - parents who love him and spend a lot of time with him, good food, stable surroundings with lots of interaction with family and friends who also love him, a routine with plenty of flexibilty...
I'm waffling on now and possibly making ds sound like the best baby in the world and like I think I'm the best mum - obviously NOT!! My real point is, actually I don't even know what my point is anymore, sorry!