The front panel was cracked on my 3GS. I could not use the phone touch screen in some part of it.
The repair is easy, just make sure you don't work in a place where the little screws might get lost if they fell on the floor. The suction pod trick (as shown on the video) didn't work as the cracks in the glass panel would let the air pass thus preventing any suction effect. Anyway, the front panel came out easily with the pointy bit of a stanley knife blade. Be careful when you remove the protection films from the new part as if you are not careful the inside one will peel off with a peripheral joint/seal still attached to it. If it does, the seal is easy enough to but back in place but one might just miss it completely and throw it away with the discarded films.
No need to get worried if you don't have the full set of special tools. If you are worried about static electricity work barefoot and don't touch any of the circuitry inside the phone.