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.