Allow registered users to blog from front-end

Hi..

I’m building social network and I have no intention in blogging myself as the network is 100% user driven, so my question is how I can let my users access the blog and publish blog posts? (front end preferably). The blog posts should automatically be published – so no admin review – but published by default, (Just a bit like FB). Instead of admin review of blog post I’m implementing user reporting of inappropriate posts instead.

Any idea there is an existing plugin or an another way to accomplishing this?

Thanks!