Help creating a Wordpress blog

I have been tasked with creating a collaborative blog/forum type web application that will allow users on a project to post topics and respond to them either through a web interface or most importantly, by email.  Meaning that users would get emails of posts and then by simply replying, via email, their response would be logged on the blog so all users could read it.

Is this something that could be created for free on wordpress?  I really do not know much about wordpress or blogging...but have used forums in the past (i.e. VBulletin types..)

Like I mentioned, the crucial aspect is that 'subscribed' users would get email of new postings and can contribute to the post by replying to that same email...and then all of the email replies can be viewed on the web page.

Thanks for any direction!!