IsoStick is a USB thumb device that emulates a CD drive and mounts ISO images. The images are stored on an internal SD card. It can be used for common images like Linux install CDs since you’d only use once or twice. No need to waste a blank CD. Instead just use IsoStick to emulate one. Since the computer sees it as a optical drive, you can also boot from it.
Free applications like UNetbootin let you make a normal USB drive into a bootable device. If you just want to mount the image on a Windows computer try Virtual CloneDrive. Linux and Mac OS X can mount ISO images natively. With the IsoStick, no need to install any software. You can support the project or find out more information by visiting their Kickstarter page.