I have heard that the front glass is easier to replace on the 5 than the 4/4S. I just did my son's 4S front glass the other night, and you basically have to disassemble the entire phone. The 5 glass involves less disassembly iirc.
Should be a step-by-step with photos for the 5 on ifixit. I bought the replacement glass for the 4S on Amazon. Should be able to find it for the 5 there too, as well as other places I'd imagine.