MSDN, Mounting ISO images as virtual drives in Windows XP
From the MSDN site:
Mounting ISO files
virtually
The following tool for Windows XP allows image files to be mounted virtually as
CD-ROM devices. This tool is provided here for your convenience, and is
unsupported by Microsoft Product Support Services.
Virtual CD-ROM Control Panel for Windows XP
Uses the VCdRom.sys driver file (placed in c:\Windows\System32\drivers) and the VCdControlTool.exe configuration GUI to mount DVD & CD ISO image files as virtual drives, saving the time and cost of burning the file to disk.