For starters I would just take off the chainring protector and then the outer larger chainring, which is probably bolted to the smaller inner one. That's what I did to my single speed when I converted it. You probably need a screwdriver and a big adjustable wrench to take apart the bottom bracket/crankset apparatus. Here's a picture of my Schwinn Continental so you can get an idea what it will look like afterwards. I was thinking about replacing the back cassette with a BMX freewheel as others have said, but after consulting with a LBS I heard it would not be worth the effort and money to free up a little bit of weight. Also, older wheels may not be able to be trued correctly b/c the spokes may be rusty/dirty and the threads stripped.