Door arm rests
 

In the front seats of my X5 the outer armrests are beginning to
come apart. Can't figure how they come off.
I would like to get the armrest recovered soon.

They don't come apart easy. You have to pull the door panel off the car and then drill out a bunch of plastic rivets I believe. They may even be glued underneath at some points.

Edit: Here you go... plastic rivet locations

http://i.imgur.com/97EM5yY.jpg

If you use an oversized drill bit you can 'gently' take just the 'cap' off the rivet. That will leave the body of the rivet still attached. After repairing, or in my case, re-glueing the leather back in place, you can use a button head self tapping screw (8g x 15mm) to re-attach the armrest. Screws are known as timber stitching screws here in Australia.

^A dremel with a cutting wheel is what I usually use to remove just the head of the rivet. Good tip on the screws though upon reassembly.