It is a U-joint and it is actually pretty easily done with some basic tools. Here is a short write up of how to do it:
http://www.myjeepxj.com/index.php?page=u-joint-replacement
How to replace spark plugs in a 1989 jeep cherokee?
No, few too many differences.
as long as the same instruments are there then yes.
YES
No.
How do you change a power steering pump in a 98 jeep cherokee?
It can be done, but it won't be a simple "plug and play" swap.
we are not sure
trade it
Most parts are interchangeable as long as it's the same engine type.
yes NO, The 89 uses a speedometer cable where the 92 is electronic.
Engine sizes, models? Not enough info to reply. My instinct is to say NO.