Is is possible to let reg’d users post? within a format?

This might be a dumb question, but is it possible to let registered users POST content (as opposed to comment on posts) to your blog/site?

If so, is it possible to have them do so by means of a form? i.e. with text boxes, email address boxes, etc.

That is, a user would register as a user to a blog. Would navigate to the form and fill out the information. The submit button would post the information to the blog (with the option of prior moderator review). The user could select an existing category or it would go to Uncategorized.

Thanks!