Sync Issues

"Is there a way to Sync iPhone with iTunes on a new Computer without first having to erase the iPhone"

Hi,

I recently bought a Macbook. So far i has been syncing my iPhone with my old PC. When i try to now sync it with Mac, i get the following message from iTunes - This iPhone is synced with another iTunes. Before we can sync it with Machne (iTunes), we wil first need to erase the iPhone.

I do not want to lose data on y iPhone.