How to format portable hard drive for mac and PC, using a MAC?

I have some files on my MAC that I would like to put onto my hard drive so I can use them on my PC. So I believe I would need to have the hard drive formatted for both computers (to be able to move the files). I will need to do the formatting on my MAC so if any one could help me that would be greatly appreciated. I would assume I'd use the 'disk utility' on my MAC to do the formatting (or if you have another recommendation).