In terms of nap-times, you should use a similar procedure as you do during the night .  As Zoe rightly pointed out, if you didn’t have consistency between the daytime and nightime sleeps you would confuse your baby by sending him ‘mixed messages.’ 

However, many parents have reported problems using the controlled crying method at naptimes so I now recommend a less-harsh adaptation for nap times.  It has been suggested that CC is less effective for naps because babies use a different part of the brain for naps when compared with night time sleep. Make sure you have black-out blinds for his room as these really help. Also, the world has a lot more things going on during the day and much more noise so you may want to consider leaving a lullaby cd on at a low volume to block out these audible distractions.

Naps can be difficult to sort out and may take a couple of weeks to get right. The first nap of the day is the place where you want to begin because this is the easiest one to tackle. Your aim is obviously going to be to get him down in his cot for that nap. Allocate a time-frame of one hour for the nap and use the technique below until the hour is up. If baby fails to sleep within that time, get him up and get him to sleep another way (car,pram etc.) and then try again the following day. Repeat the process until he’s settling for that nap, then move on to another nap.

Here is the technique to try for parents who have used CC at night time but are struggling with nap time. The two techniques are consistent so using one in the day and one at night won’t confuse your baby and cause problems at night.
The nap time technique (this is not easy btw but it does work):

1. Have a short pre-bed routine and place baby in the cot awake. If he cries, try and comfort with words and gentle head stroking. If he doesn’t stop crying, pick him up and say, “shush, shush” and softly pat his back. As soon as he stops crying, put him down straight away (you are not rocking him to sleep you are still attempting to get him to fall asleep in the cot). If he is crying and arching his back, put him down immediately.

2. Even if he cries the second you begin to lower him into the cot, make sure you still put him down all the way to the mattress before you pick him up again. Repeat this procedure correctly so that you are picking him up when he cries and putting him down immediately when he stops. After a time he should begin to calm down and cry less. If you do get him to the stage where is in the cot and is quiet, stay with him with a hand laid on his body and carry on the reassuring talk in a very soft voice. Only leave the room when you are sure he’s in a deep sleep.

3. After 20 minutes of this, put him in the cot and leave the room for 10 minutes. If he is still crying, repeat the ‘picking up and lowering down’ method for another 20 minutes and leave for 10.

As for cosleeping, Controlled Crying (also known as the Ferber Method) relies on your baby sleeping in a cot in his own room.  Obviously, this is an either/or situation.  If you are happy with your co-sleeping arrangement then the Ferber method is not for you.  In Zoe’s comment she asked whether she could incorporate the Ferber method into her current co-sleeping arrangement by leaving the room each time her baby wakes up crying.  I personally don’t think this would work and I strongly recommend it shouldn’t even be attempted.  The crucial point of CC is to teach babies to soothe themselves to sleep.  This means them waking up alone and being able to comfort themselves back to sleep without screaming out for mum or dad.  If you attempted controlled crying whilst co-sleeping your baby would not be waking up alone and the first thing he would see was his mum leaving the room.  Furthermore, when it came to making the transition to his own room it would probably mean starting again from square one. 

When you decide it is the right time to make the transition to the crib then I would advise you leave the Ferber Method well alone until your baby gets used the change.  Moving surroundings will be a stressful enough time without adding to the trouble.  I will write a separate post soon to discuss how you can make the transition as easy as possible for both of you.  Just off the top of my head, I like the idea of having a crib in the same room at first and getting baby used to sleeping in there.  You could then gradually move this further away from your bed before you make the jump to a different room.  I also think it would be wise to start using the crib for nap times and moving this into baby’s own room.  This will make the night-time change a little more familiar and easier to deal with.  Personally,  I think it needs to be a very gradual change to minimise the distress.  Once your baby has got used to this arrangement, if needed, you could start implementing the Ferber technique.   

If your baby is at least six months old and is still waking up to feed through the night, you should consider reducing the night-time feeds.  This is especially crucial if you are a cosleeper who wants to move your baby to his own crib because if  he is really hungry at night he would wake up and scream his head off if he suddenly found himself alone in a room with no mum or food at his disposal! The technique is called calorie shifting and works by increasing the day feeds to compensate for the night. Full details are in this post: Reducing Night-Time Feeds

Here is the other relevant post:

From Bed Sharing (Co sleeping) to Cot- Making the Transition