Russ Anber is a boxing coach from Canada.  He is also a cutman and can be found doing commentary from time to time.  One of the fighters he used to train was current IBF Middleweight Champ David Lemieux.  In the following video, they demonstrate how to throw the straight right hand also known as the cross.  Check it out.

For some more detail about throwing the cross, refer the BOXING 4 FREE section Cross under Training at the top of the site.