If you’re looking to take advantage of compressed files, or even iso image files and being able to mount them without burning them to a disc or such, then Pismo File Mount Audit Package will come in handy. It has full filesystem support, and explorer integration (so that you don’t have to launch the program every time you need to use it). You can basically right click on any iso, zip, or even compact folder system and mount it just like a drive. This allows you to keep the same file structures without having to unzip, or install certain things which makes things very usable.
Freeware for Windows 2000 up to Windows Server 2008.