Currently, the Services and Daemons chapter of the Deployment Guide for Fedora 15 only documents how to start, stop, enable, disable, and check the status of services by using the systemctl command. It does not describe systemd itself, nor does it explain the concept of systemd units. This chapter should be extended to provide reasonable documentation on these topics with the focus on .service and .target.
Removing myself for these bug components as I'm either no longer involved in that aspect of the project, or no longer care to watch this particular bug. Sorry if you are caught in a maelstrom of bug changes as a result!