Jenny-ka, one of our mangakas has stumbled upon this website which she thinks some of us here may be interested. (since she is having some difficulty with the forum, I am posting this for her)

Manga University is an online art and critique site where you can submit your art work and get free critiques. It also publishes a printed art book, called Manga Without Borders which features art work submitted by amateur artists or people who would like to see their art work published. It is free to submit your art, but if you are accepted, you will have to pay $100 (not sure what currency) to have your art work printed in Manga Without Borders, but you will be receiving 10 copies of the art book, and have the opportunity to refuse the offer if you are selected. (I just briefly skimmed through the site, for more info, visit the link below)

Here's the site for more info.
http://www.howtodrawmanga.com/

Here's the link if you would like to submit your work:
CLICK

-Ki