Its not as hard as you may think to be honest!
The gearbox tunnel will need modifying on the drivers side to make room for the transfer box and if there arn't any there already a couple of half moon shape bits will need removing from the front chasis rails to allow clearance for the drive shafts.
Other than that the rest is a simple remove and replace with 4x4 parts!
The list is as follows:-

Sump + front diff
front driveshafts req'd
Engine mounts
oil filter remote housing
front crossmember
steering rack
hubs
tca's
front roll anti bar
front suspension
front brakes
gearbox and mount
clutch release bearing
exhaust
prop/s

There are probably some other odds and sods but thats all i can think of at the mo