Aperture Hot Folder v1.1 for Mac is a freeware AppleScript application that will monitor a folder and automatically import into Aperture photos arriving into that folder.

It's meant to be incorporated into tethered workflows, where an application such as Canon EOS Utility or Nikon Capture Control manages the link to the camera, enabling the Aperture Hot Folder application to watch these applications' target folders and automatically import new photos into a user-selectable Aperture project. But it ultimately can be employed to watch any folder, regardless of how the pictures are landing there, including from a Wi-Fi camera connection.