I always loved this little tutorial.  It is from the creator of GANTZ  GANTZ has been made into a manga, movie and anime.

The author uses 3d models, traces over them and adds detail and walla he has a manga.

Here is some more of his current work.  That might be an idea to make your own manga or anime.

In the next few posts I will be showing you more of the stuff I will be working on and I will be using this method more readily but using Poser similiar to Brian Haberlin

Here is his method.  I hope you can glean some off this method.