ConGo SE is a Windows shell extension for working with C64 file formats.
http://www.editorix.org/congo/html/c...extension.html
It's pretty cool and easy to work with. Though it crashed a few times last time I was using it. I used it to make some .d64 compilations with my favorite games. There's also a plug-in for it that allows you to import C64 graphics into Photoshop.