Well we all think Apple has switched syncing completely to iTunes, where you can shop exciting stuff. But as i recently bought a new mac an did a clean start, I was missing my old sync-warning message that allowed me to review what flew from my iPhone to my mac. So here’s the workflow to get that warning back.
1. Open up iSync
2. Open up preferences
3. Chose “any”

Close everything and you are done.

Don’t get confused, if there isn’t any device registered in your isync. It’ll work anyway.