iMac Superdrive Replacement
Getting the glass and LCD panel off without snapping cables is tougher than you may think, my recommendation would be to have it repaired by a professional. I'm not sure how much prices vary around the world but we would charge around £90 for the part and £40 for labour (if it's an optical drive) plus taxes. As things go, it's not an expensive repair.

If you're hell-bent on DIY then I'm sure there are places out there you can get parts and manuals/take apart guides. It may end up more expensive if you damage anything yourself, and of course there's no warranty on the repair!

The other option would be to use an external drive. There are loads of options out there at varying price points.