Need Sleep

Lynze
I need some help. My son is 15 weeks and he used to wake up twice a night and now he wakes up every 1.5-2 hours and wants to nurse. He falls asleep attached to me and when we move him to his pack and play in our room he wakes up an hour to two hours later. Last night when I tried to not let him nurse he cried for 30 minutes and it broke my heart and we were both crying. He ended up falling asleep in my arms and the next time he woke up I let him nurse. Needless to say I got hardly any sleep which makes for a fun morning of getting ready for work.
So I need help with the following:
1. How do I get him to nurse less or go back to waking up twice?
2. How to start transitioning him to his crib/own room?
3. Any book recommendations or blogs or whatever to help get him to sleep longer and start the separation process?
Thanks from this walking zombie sleepy mom!!!