Yes we tried it and it was successful. DS was about 7 months when we started and was waking 4 - 5 times a night, at best.
After the first session he slept for 6 solid hours that night. Each night after got slightly worse but not as bad as before he had the session.
We had weekly sessions for quite a while so it was a bit expensive. But I don't think we'd have got the improvement otherwise, so it was worth it for us.
Each week followed the same pattern i.e. great night sleep on the first night after the session, then getting slightly worse each night until the next session.
Over time we were able to reduce our sessions and then eventually stop. He's still not a great sleeper now at 3, but will generally sleep through 4 - 5 times a week and only wakes once a night the rest of the time.
I tried it on my 9 month old at the time (nearly 2 now) didn't work but she did enjoy going she still doesn't sleep. How was your birth? Is your child niggly? I think it helps for ids that had forceps delivery or traumatic births etc as it straightens them out and balances any unevenness. That's my uneducated take on cranio osteopathy anyway!