Guest Blogger
http://www.blogxpertise.com/2013/02/guest-poster-submission-form-blogger.html
The concept in a nutshell:
use Blogger's posting using email, or "Mail2Blogger" functionality to have guest posts submit posts IN DRAFT to your Blogger site
the guest post submissions will be structured because they will be via a Google Docs Form that you can set up and customize, with the submissions being added into a Google Docs spreadsheet as well as emailed to your blog in the proscribed format.
you set up a "guest poster" gmail account and add it to your Blogger site as an author; all guest post submissions will be made via that account,
you as the admin can choose to publish or delete any submissions that meet your approval