A: For Windows 7, Microsoft’s Windows 7 USB Download Tool could take an ISO file as input and write it out to a USB device, creating a bootable USB device containing the Windows 7 install media.

This same application works for the Windows 8 Developer Preview ISOs as well.

Just download it from the Codeplex site  or the Microsoft Store (the link is near the bottom right, just search for Windows 7 USB/DVD Download Tool).

Then pass the Windows 8 ISO as the input. Here’s a screen shot below, showing an example.
win8isotousb_0