I'm wondering if anyone has tried this. I've successfully set up the inbound email, however all mail and attachments are simply dumped into the folder. What I'd like to do instead is set up a rule that somehow creates a new folder based on either the subject line or sender, and therefore dump the contents of the email into its own unique folder.
that should be a relatively easy task - when the email is dumped into your folder, content rules are automatically triggered (if configured). So you should be able to set up a content rule with a custom JavaScript action that creates the sub-folder and moves the email and its attachments into that folder.