Switching from PC to Mac, will iphone need to be reformatted?

[teh hudge party]

With an iphone that has previously been synced only to a PC, how do I go about mating it to my MBP? FWIW, my current itunes library is on an external drive...when I configure itunes on the Mac draw from this drive, will it then be able to sync with the iphone?

 

[atlanticza]

I sync with both OS. No problem.