OSFMount supports mounting images of CDs in .ISO format , which can be useful when a particular CD is used.
OSFMount allows you to mount local disk image files (bit-for-bit copies of a disk partition) in Windows with a drive letter. OSFMount also supports the creation of RAM disks, basically a disk mounted into RAM. This generally has a large speed benefit over using a hard disk. As such this is useful with applications requiring high speed disk access, such a database applications, games (such as game cache files) and browsers (cache files).
For additional information regarding this software, please see this GROK article: OSFMount: LSU Overview.