Sample p-list file for an OS X daemon.

com.whymarrh.apps.mediakeys.plist

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
    <dict>
        <key>Label</key>
        <string>com.whymarrh.apps.mediakeys</string>
        <key>ProgramArguments</key>
        <array>
            <string>/path/to/the/executable/file</string>
        </array>
        <key>KeepAlive</key>
        <true />
    </dict>
</plist>