It's not too bad if your organzied. I changed mine to the black one. My tips would be to first print out the screw chart.
If you changed the screen before, it shouldn't be too bad because you're only going to be taking a few more things out......( Home button, speaker dock, Headphone jack/silent button/volume button flex cable, Power/speaker flex cable.
OH! Something important. Do buy some adhesive strips for the screen. Buy a few (Even though you only need one.) but you can use those strips for other places that orignally had adhesive.
Another thing important to replace is the LCD Heat Shield Dissipation Film. Its a strip that you place on before the screen. It prevents over heating.
Umm...Oh yea you'll need the mesh grills for the bottom speaker.
But do watch the videos on this site first to get an idea what you're going to get yourself into.
If you have any questions or ran into problems let me know. (firstname.lastname@example.org)
I don't work for apple but I sure feel like a pro with the amount of things I did to this Iphone!!!!