Jeremy Herve on "[Plugin: Jetpack by WordPress.com] Jetpack Post By Email"

Is there a way as an administrator to authorize other users (authors) to post via e-mail?

Once you activate the Post By Email module, all registered users with publishing privileges will be able to use Post By Email. They will see a button mentioning "Enable Post By Email" on their profile page.

If you do not see such button, could you contact us via this contact form so we can have a closer look?
http://jetpack.me/contact-support/

Thanks!