I believe the following models are the ones that can read Wii Discs
GDR-8161b
GDR-8162b
GDR-8163b
GDR-8164b
(there may be a couple others)
The following link has all the information you need regarding DVD Drives for Wii Discs
[Only Registered Users Can See Links. Click Here To Register]
Also USB Gecko can be used to back-up wii games.