mickeddie: the version you want will depend on what your cpu is. If you have a 64 bit cpu, you can use the 64bit version but there is also a lot of compatibility issues using older programs under a 64bit OS especially with games. You may just want to try the 32bit version first.
ISO files are disk image files meaning when you burn them to a DVD they will be a bootable DVD that you put into your drive and autorun or doubleclick to execute the install.