That's basically what this thread is about. There's several suggestions here:
http://www.automotiveforums.com/vbul...d.php?t=542145
Those things can be a PITA. Try spraying some penetrating oil on the splines of the half shaft. Let it soak in and then spray a little more. Hold a 2x4 over the shaft to protect the threads and then beat the hell out of it with a BFH. After it breaks loose and starts to move back, remove the three bolts ( 18mm if I remember correctly) in the back of the hub and work it off over the shaft.