Burn a data CD or DVD to ISO 9660 (readable on PC)

I'm trying to burn some files onto a CD-RW (old school, I know) but I need it to be readable on a PC. How do I do that on Snow Leopard? I know how to do it normally, just pop the CDRW in the drive, it appears on the desktop, drag stuff to it, open the burn folder, hit burn and take a five minute break.

But this puts the CD as a HFS volume, and is only readable on Macs.