Hi, Mac57,
The firing pin is held in by a cross pin that can be driven out. Since you can take the gun down, you should do this with the hammer out of the gun. Support the hammer on a work block with a hole for the pin, use the right size drift punch and drive it out (either way). On some of the older Colts, it is nearly impossible to see the pin as the hammer was polished after it was installed, but it is there. You will probably not be able to get it looking quite so good again if you reuse the original pin. If appearance is important, you can buy or make a slightly longer pin and file it down and then re-polish the hammer.
I can't help with the cylinder binding without seeing the gun, but you might check for drag marks on the front of the cylinder to see if the cylinder face is not square and part of it is hitting the barrel.
Jim