How do I set up sync to mobileme on new mbp

Hi there, sorry if this is an obvious answer but this is my first mac. I have mobile me and would like to know how to sync it with my mac. I go to system preferences and then mobile me under the internet and network section. When I click on the sync button and it takes me to all the things that can be sync'd I click the box that says sync with mobile me but nothing is highlighted. I cannot select anything to sync and cannot select whether I want to sync manually or auto. Am I missing something.

Thank you

No but I signed out and then in and now it works. DOH, sorry,

Thank you for your reply though. Very much appreciated

Everything syncs fine except for the contacts which is says it cannot do due to inconsistent data? Does anyone know what this means and how I can get around this problem