Thanks! Vagrant was really made to target the development environment, since the production world is pretty well covered in terms of deployment (whereas John and I thought that the development side of things had been neglected).

But keyist answers your question best. I've quoted his response below:

  "Could you perhaps turn convert a Vagrant project into an EC2 instance for deployment?"

  That's where Chef comes in. Vagrant uses Chef (http://wiki.opscode.com/display/chef/Home) for provisioning VMs. It's basically software configuration management (same category as cfengine or Puppet) -- you write cookbooks that specify how a system should be set up (see http://github.com/opscode/cookbooks/raw/master/nginx/recipes... for an example).
  If you write your Chef configuration the right way (ie not hardcoding anything to a set of system specifications), you can take the same set of Chef cookbooks you write and deploy to EC2 or any other Linux box, virtual or no.
  So with Vagrant you can essentially pass around a virtual machine configuration amongst your team and be confident that the entire team is coding and testing in a near-exact replica of the production environment. Not that this was impossible before, but Vagrant streamlines the process.
  I've provisioned 20+ servers with Chef and once you have a solid base configuration you can take your attended time on a full server stack (nginx, memcached, post{gres,fix}, munin... the works, essentially) to less than 10 minutes.