Synchronizing my iPhone

Hey everyone,

I want to synchronize my iPhone to my new macbook pro from now on. The previous computer I used is a windows and I used to synchronize my iPhone to the iTunes on that. But now I want to use the iTunes on my new macbook. Can I synchronize my iPhone without loosing contacts, music, apps? And how do I get my purchused music from my iTunes on my old computer to the iTunes on my new? I am logged on with my apple ID, but don't see my purchuses anywhere. And don't see any of the other music/apps that I see whenever I opend the other iTunes.

Help would be much appreciated. Thanks!