I'd like to take a Linux ISO (e.g., CentOS, Ubuntu), and create a bootable USB drive. (It will be used for booting on a stock PC, not on the Mac). How do I go about creating such a drive using a Mac?
Open Disk Utility (you can find it in the Utilities folder). Insert your USB drive, and select it in the left pane. Choose the tab "Restore" on the right side of the window, drag the image file into the "Source" field and the USB drive into the "Destination" field. Click the "Restore" button.
That should do it.