http://frenchfragfactory.net/ozh/archives/2005/09/20/how-to-wordpress-gmail-blog-by-email/
Here is something I may have a look at someday : how to use WordPress’s Blog By Email feature with a GMail account. And for the Cron part, for those not having shell and crontab access, I suggest either Skippy’s WP-Cron or PHP crontab replacements.