You should be fine then if you have done plates before.
You will need to unbolt the water pump & drain the coolant to get the clutch cover off.
I only know of one other member that has needed to change his clutch plates out of thousands of XT members. Check the clutch cable adjsutment first.
This may help you.
http://www.xt660.com/showthread.php?t=9392
Good luck