Aidyn began sleeping through somewhere between 2 and 3 months old. The thing that helped was giving him a dreamfeed at about 10pm just before we went to bed, this would seem to tide him through till early morning.
That was our first experience of him sleeping through, but over the next years the sleeping is very much 'on again, off again'.
We usually get a bad couple of weeks sleepwise every 3 or so months, but it has settled down a lot more in the last 6 months (he is nearly 2.5 now). Needless to say whenever he is sick, sleeping well at night always goes out the window!