I've just fixed mine tonight. Ordered the part from eBay. The old glass was very hard to get off, but do-able. I used heat, a blade, a guitar pick and a very careful hand! Not that much to damage underneath though. The ribbon connector is very small and stuck down well... You'd have to really scratch at it with something hard or cut it to do any serious damage. There is the possibility water could get in... there are gaps around the camera lens and flash, although I didn't actually take them out to see if the gaps lead to any holes through the phone chassis.
