Tools required: Phillips size 0 screwdriver
Remove the battery cover and battery to allow access to six screws. Remove these screws.
Now lift the circuit board away from right to left, as shown below. It's held in place quite tightly. The board will still be attached by a few ribbon on the left side.
Unclip the grey part from right to left, shown below, to reveal another ribbon (circled). This attaches like a plug and socket. Simply lift it up to unplug it
Your phone should now look like the picture below.
Now remove the lens which covers the screen. It is held on with a tacky glue and will require some force to remove it.
Your phone should now look like the image below.
The LCD screen and frame are stuck into the front of the phone by a tacky glue so carefully peel it them away (you don't want to bend the frame as you'll need to put the new screen in this).
Now remove the LCD screen from the metal frame and replace with new. Reverse the whole procedure for reassembly.