Oracle Enterprise Manager 10g Grid Control Implementation Guide P2
Oracle Enterprise Manager 10g Grid Control Implementation Guide
and many other types of targets as well. It is best practice to run either Grid Control or Database Control, but not both, although you can run both concurrently.
Grid Control vs. AS Control
How is Grid Control different from Application Server (AS) Control? In short, as just one of many target types it monitors, Grid Control monitors the Oracle Application Server, whereas AS Control administers the Oracle Application Server.