hi olive oil, and every1 else, read this thread with interest as have very sim circumstances with my ds's 1and 2.
first off, it is absolutely essential that both adults are commited to doing it if you do try coz neither one of you will be strong all the time and even when you know that the crying is not actually abandonment and despair, but a resistance to change, there will be weak moments and consistency is the thing that will make the whole process happen in a few days, rather than weeks.
so, we did do cc with ds1 when he was about 5 months. felt awful at the time as we were so sleep deprived i didnt know my arse from my elbow, but for a few nights of 'cowering somewhere looking at the monitor' and 'grimacing at the TV' - so true for us too! he actually went to sleep, slept through and has been a 'good' sleeper ever since. obviously a benefit to him as his days were less tired and he was more secure about waking in the night and going back to sleep unaided. benefits to us were immeasurable!! felt like getting my personality back!
(BTW - we did the same routine for night wakings; 2 minutes, then 4 then 6 etc. he got the message pretty quickly)
so anyway, after a couple of months, when detail had faded in memory and we had all been sleeping properly for a while, i was SOOOO pleased we had done it and we clapped ourselves on the back for being 'strong' enough to do 'the right thing'.
then ds2 was born 13 months after ds1 and somehow it was a completely different story. not sure exactly how we drifted into doing things so differently, but by the time ds2 was 15 months (a few months ago) we were still getting up for him between 2 and 6 times a night to put a bottle of milk in his gob (only way he would go to sleep. only ever went to sleep on the boob before 6 months) suddenly realised how old he was and thought, what are we doing?? also expecting ds3 shortly so this was a concern too.
like someone said, part of it was that we didnt want to let ds2 crying wake and disturb ds1's sleep pattern.
so anyway, in the end, worn down by exhaustion and that delightful feeing of guilt/failure that only a parent really knows (isnt that a joy??) a couple of months ago we hired a 'night nanny' to sit through the 4 nights of cc with ds2 instead of us. he gave in shockingly quickly and was going to sleep without milk, in his own cot, and sleeping through by night 3. amazing, and such a difference to us all! best few hundred quid ive spent ever!
now he is in his own bed in the same room as ds1, they go to bed/sleep together and both sleep through (most of the time anyway, not counting teething/leaking nappies/bad dreams/any other night wakings) have to admit i do give them both milk in a bottle to go to sleep initially (bad mother. i know their teeth will fall out!) but like i say, all worth it in the not very long run
so, in a REALLY long drawn out way, im saying its ok to do it coz you need to for you. you DO need your time to yourself to recharge and unbroken sleep once in a while is essential for sanity. and what feels horrible for 3 nights (less horrible each night after the first) will benefit you ALL SO MUCH after a very short time. if the baby whisperer way feels better, do that i'd say - always do what feels right for you and the particular child and never apologise for following your own instincts... i dunno, cc worked for us in both cases so far and life is happier in our house as a result so thats just one opinion
good luck, whatever you do!