Since I know you all want to see it because of his wacky style, and because many of you STILL want confirmation that there isn't any training in the World that will give you the punching power he had for a man his size, here it is.
CHEESY music promo vid, but you can see some of how he Shadowboxed:
http://www.youtube.com/watch?v=X6HBka9Mu98
Part of a Documentary that shows the Prince's training approach (you also get a look at the younger Marco Antonio Barrera):
http://www.youtube.com/watch?v=_ITe-EWHNmM
And here until about minute 5:
http://www.youtube.com/watch?v=9ouIoMJWED
And of course the fight with Kevin Kelly, which turned out to be arguably the most exciting fight in FW History:
http://www.youtube.com/watch?v=QEbBVgdF8SM
(follow the links for the rest).