Many software companies make their CDs or DVDs available online in the form of ISO disc images, and there's no doubt they're easy to use: just download the file, burn it to CD or DVD and you're ready to go.
Virtual CloneDrive can make the process even easier, though, by mounting your image file on a virtual drive. You can then browse the disc's contents using Explorer or any of your applications, without ever needing to burn a copy to disc. Of course this won't help it's a disc you need to boot - a Linux LiveCD, for instance - but if you simply want to browse the contents of an ISO image then this is a simple and hassle-free way to do it.
And Virtual CloneDrive is supremely flexible, too. The program supports all the main image formats (ISO, BIN, CCD), can manage up to 8 drives simultaneously, supports 12 different languages for the interface and runs on every version of Windows from 98 through to 7, both 32 and 64-bit. Grab a copy immediately.