How to remove and disable spotlight

To turn Spotlight Indexing off and on in Mac OS X 10.6 Snow Leopard, and to remove the Menu Bar Icon, follow these steps…

To turn Spotlight Indexing off in open Terminal and run this command:

sudo mdutil -a -i off

To turn Spotlight Indexing back on, repeat the above command, but change off to on. To remove the menu bar icon, run this Terminal command:

sudo chmod 600 /System/Library/CoreServices/Search.bundle/Contents/MacOS/Search

You’ll then to restart the menu bar with killall SystemUIServer to see the icon vanish.

Source: macosxhints