There is currently a problem with the Your Art submission form. I’m working on getting that up and working. In the meantime, if you have something you would like to submit, please send it to me at rio[at]this site’s url.com. Replace “this site’s url” with mangatutorials and [at] with @.
[UPDATE: April 22, 1010]
Problems with the Your Art Submission form has be resolved! You can now use it to send in your submissions. Please be aware that you may only submit the following file types: jpg, png, bmp, gif, tiff, xcf, psd, zip, and rar. If you are sending multiple submissions, be sure to send your work in compressed as a zip or rar file or, if you prefer, send it along directly from your email to me at rio[at]this site’s url.com as multiple attachments.
If you have any questions, be sure to check out the Your Art FAQs page.