I had mine out today, the procedure is not too diffulcult.
I breifly explain, but really it's step by step common sense. Start on releasing the dvd drive main board (where you fit the mod-chip)
1) unclip all the leads/bus connectors (1 flip catch, 2 double side catches, and 1 push fit)
2) where there are hard soldered wires on the board edges (1 group of 4, 1 group of 2), it enough to just release the wiring from the routing clips to have enough room to manouver the board to the side, which is all you need.
3) remove the 2 screws holding the board
4) now you can move the board to the side and see the 1 screw holding the silver shield in place, remove it
5) around the edge of the siver shield there are 4 clips, bend them out with a small screw driver or needle
6) now you can carefully remove the silver shield and have access to the laser assembly
5) to remove the laser assembly you need to remove the slide rod, this is easily done by removing the securing screw and small plastic bracket at the end of the bar (console edge side), then slide out the rod
6) the laser asembly is now free to remove. (remeber to transfer the plastic worm arm and spring from the old laser assembly to the new when refitting
)