My iPhone 4S won't sync to itunes?

My iphone was just recently activiated, and it won't connect to itunes. It shows up that its charging and it connects to dropbox, but I can't get it to sync. I have tried several different cables, but no luck. Songs that I've purchased in itunes show up, but everything else like videos, apps and songs uploaded from CDs aren't there.

I've tried looking in my settings, but I can't find anything that might help. Any pointers?

I use an iphone 4S and a Macbook Pro with Mac OS X 10.5.8 (Leopard)