I've been using SW 2007 for a couple years now and I've found the easiest way. Enter a sketch plain and draw a diameter, then take a line and draw it from top of the circle to bottom, take the trim tool and cut one for the sides off so you only have 180 degrees of the circle left, then draw a center line right on top of the vertical line. Then enter the revolve feature and rotate 360 degrees and you have a ball.

Bane