To Disable Spotlight for Mac OS X you can stop the Spotlight processes from being invoked by launchd. To do so use the following commands:
launchctl unload -w /System/Library/LaunchAgents/com.apple.Spotlight.plist
launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
To re-enable it you would simply load up your launchd processes again like so:
launchctl load -w /System/Library/LaunchAgents/com.apple.Spotlight.plist
launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
