WP Email-to-Facebook is a WordPress plugin by Xavier Media that will email the Facebook page you’ve created for your company, organization, band, brand, cause or topic every time you make a new post in your blog. You can specify different emails for each categories, so that if you have for example one category for Charity posts in that category can be emailed to one page, while posts in any other category of your blog can be posted to your corporate page at Facebook.
Download and info: http://wordpress.org/extend/plugins/wp-email-to-facebook/