Despite being such a small thin phone, the housings on this model can easily be changed. You will need a a small plastic shim in order to remove the housing. Instructions:
1) Remove the battery, SIM card and rear housing.
2) Remove the RF bung (the small plastic piece to the left of the antenna cover)
3) Remove the antenna cover. There are two latches on either side which prize up to allow this part to be removed.
4) You should now have a bare back of the handset.
5) The front cover can be removed by applying leverage to the small gap between the housing and chassis. Generally, working from the top usually works best.
6) Once you are in, run the shim around the phone to clip the cover off.
7) Replace with the new front cover
8) Replace the rear cover, remembering to replace the bung in the same place.