GTD and Outlook SYNC Prorblem Looking for solution PLEASE HELP

Hi there all of you. I implement GTD. I have a laptop, a desktop and a windows mobile phone. I keep track of all appointments and day only actions in my calender. All my lists are in the notes section of my windows mobile phone and outlook.

I am able to sync my laptop and windows mobile phone via outlook.

However the major issue I have is that I have multiple devices therefore how do i keep all of my computers in sync. How do I keep my outlook on my pc and laptop in sync? I have looked into microsoft exchange server. However this can be quite costly nad my email account is based with hotmail.

Any Suggestions will be most appreciated.