That's funny. Your idea to convert a PS fan into a regular case fan is something I did a while back. I had an old PS that was just sitting around, and I decided to make it into a case fan.
THe only problem you'll have is finding out if the fan is a 5v or a 12v fan. It should tell you on the side of the fan hopefully. the black leads are for grounds, the yellow is 12v, and the red is 5v. If the fan is 12v, it will still work with 5v, but will just go slower.
You just have to strip both sides, and then do a quick solder job. It's easy to solder them together, then you just have to put some electrical tape on them. Once you're done with that, you have a case fan ready to use.
<- a picture of the work after I had soldered 2 PS fans onto 1 lead. If this doesn't help, sorrry, and hopefully you get some help on creating a clear side panel.