To burn an ISO file on OS X you need to use either Disk Utility or Toast Titanium. With Disk Utility, insert a blank CD, select the CD burner in the drives list, find the Restore function in Disk Utility. Drop the .iso file into Source and the CD-R/DVD-R into Destination. Restore the iso and you should be able to boot from it. With Toast this should be even more trivial.