One quick download later, and I was set up and ready to go. Daemon tools gives you a nice, simple menu driven tool that sits in the Windows taskbar, and allows you to set up as many virtual drives as you want, and use them to mount CD and DVD images. It's ideal for working with resources like the MSDN subscribers download library, where Microsoft has switched to using ISO images for tool distribution. You can use Daemon Tools to work with other CD image formats, and it'll even emulate most of common the disc security schemes so you can use it to work with ISOs of games (an excellent idea if you're taking a laptop on a plane) and movies - even handling region setting.
It's a lot neater than the old Windows kernel toy I'd been using as an image mounter - though I'll still stick with Undisker for image creation.
Oh, and it's free for personal use.