I disabled Spotlight and its Metadata Framework in OS X 10.5 by moving two files to a safe location that they can be restored from if necessary. The files are:
- /System/Library/LaunchAgents/com.apple.Spotlight.plist
- /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
In 10.5, there is no spotlight entry in /etc/hostconfig, and there is a note there that states that this file will be going away in the future.
[robg adds: This hint supersedes the info found in this one, which listed the 10.4 method of disabling Spotlight, which doesn't actually work in 10.5]

