am having exactly same situation with my ds aged 2 weeks + 3 days so lol at 3am whilst dd and dh are snoring away....
with dd I didnt realise how easy I had it - but I also think we forget what ALL newborns are like. hungry, grizzly tummy and always with their eyes closed, whether sleeping or crying. We just need to get back into the swing of it.
having been quite strict with DD (no dummy, putting down to sleep in cot etc) I have decided to go completely free range with DS for the beginning tough bit. Slings, dummies, co-sleeping, breast feeding to sleep....and offering a formula top up if he looks like he needs it + wholly formula nighttimes.
Contraversial I know - and bound to impact on my supply - but with siblings, I took the view that a fuller baby would allow the rest of the family some sanity and sleep. With just my DD, I had a responsibility only to her so constant BF was the right choice - with more, it isnt that simple anymore.
Having said that, DS is now overeating, vomming and screaming, so easier night wakings are no longer...so much for the compromises [blush}
Book I would recommend is Healthy Sleep Habits, Happy Child (Marc Weissbluth). Basic approach being, if you have a fussy/colicky baby, do whatever it takes to settle them for the first 4 months and dont worry about the long term sleep habits.