Digital Tutors is a terrible company to learn from, it's run by "when you can't, teach" people.
I don't know about guthrop's tutorial, but ZBrush is fairly essentially to the pipeline for creating quality characters these days, unless all you want to do is make low-poly hand-painted pixel-arty characters for an indie game, but you're really limiting yourself that way.
Look up the "Eat3D Character Production" series on CGPeers. It covers the pipeline from ZBrush to Maya. Eat3D and Gnomon are the prime places to learn from, they're tutorials and teachers are people who actively work at big name studios in the industry for film and games. Gnomon tends to lean more towards the more advanced students, while Eat3D is more suited for beginners, though Gnomon does have some beginner stuff too.