If this is a new mac, you can use Migration Assistant to move your data (including iTunes) from you PC to your mac (see http://support.apple.com/kb/HT2518). This method will move your contacts and calendars to your mac, allowing you to continue syncing these with iTunes if you have been. Or, if you want to just move iTunes so you can maintain you ability to sync your phone without losing data, move the entire iTunes folder to your mac using one of the methods described here: http://support.apple.com/kb/HT4527. Then create a backup of your phone on your mac by, prior to connecting your phone, opening iTunes and disabling automatic syncing (iTunes>Preferences>Devices, check "Prevent...from syncing automatically"). Then connect your phone and right-click on the name of your phone when it appears on the left sidebar of iTunes and Transfer Purchases (to transfer any recent purchases to your iTunes library); right-click again and select Backup. If you have been syncing contacts and calendars be careful not to select to do so on the Info tab of your iTunes sync settings unless you have transferred your contacts and calendars to your mac. If you attempt to sync these to an empty iCal and Address Book iTunes will delete your calendars and contacts from your phone.
Yes this is a new mac. I am not so much concerned with contacts and calenders as i use exchange at work and everything is stored on our servers. Im mostly concerned with my application databases such as angry birds and gas mileage logger. I will try what you suggest and just keep my backup on my pc just in case.