Gnomon tutorials are fantastic and very easy to follow from my experience, I used them a lot when I started out. They do go into a lot of detail though so it may seem a bit daunting at 1st and you will need to watch some parts again and again. This is because they teach you how to create work to a professional standard so you get a good idea of what is required to create great looking work.
With regards to zbrush it is a great piece of software and helps create great 3d art. I always model my base meshes in maya and get the uvs done using the roadkill plug in. This allows me to create simple base meshes with good topoplogy that can then be brought into zbrush as sub tools for sculpt and texture work.

Good luck and look forward to seeing your work in the forums.