Does changing a daemon's plist file extension prevent it from being loaded?

launchctl list and sudo launchctl bstree will show you the jobs. You'll need to read up on the mach_init part as well as be aware that launchd gets more and more of the pie as you go from Tiger/Leopard/Snow Leopard/Lion - your in general question is basically "walk me through launched" - The command mdfind dashboardadvisory will search in the areas hidden by default in spotlight as system files.
@bmike
PS: post it as an answer if you want, so I mark it correct.

You can also disable a given LaunchAgent or LaunchDaemon with launchctl without renaming the file.

sudo launchctl unload -w /Library/LaunchDaemons/com.whatever.you.want.to.disable.plist

If you omit the -w, it'll only disable the task for the current boot. This is handy for testing if disabling a launchd task will fubar your system - if you run into trouble all you'll need to do to fix things is reboot, and things will be back to normal. Otherwise you'll have to boot into single user mode and manually edit the plist to re-enable the launchd task.