Undertray off.
Support sump on a block of wood (with a trolley jack underneath it!).
Jack up slightly to relieve weight on mount.
Mark on chassis where mount is located.
Undo mount to chassis bolts.
Undo central bolt.
Jack up to make removal of mount easier.
Replace mount and reverse above procedure.
From memory, I think that's all thats involved. Don't know if the procedure is made more difficult by having A/C because I have a Cup?
EDIT - Seems I'm late to the 'obvious' party...