Part 1: 
        
http://www.xt660.com/showthread.php?t=20735
         
         Part 2: 
        
http://www.xt660.com/showthread.php?t=20736
         
         Part 3: 
        
http://www.xt660.com/showthread.php?t=20737
         
         Part 4: 
        
http://www.xt660.com/showthread.php?t=20738
         
         Service your steering head bearings: 
        
http://www.xt660.com/showthread.php?t=12483
         
         All the tools needed (or ways to get round needing them) are covered at various points within the threads, just read them though before you start.