With the Mac OS X 10.2.3 update, the ability to change the default search page on all web browsers seems to have disappeared. In System Preferences -> Internet -> Web, there used to be a setting to change both the default home page, and the default search. The search is gone; Apple is overidding it with their Excite.com web-search.
[Editor's note: I hadn't noticed this until reading this hint ... that's probably because I never used this setting and wasn't really sure what it was supposed to do (I do all my searching with a Google assistant or directly in the browser). I wonder if it might be possible to paste the "key" setting from a prior version into the plist file to restore the functionality...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030106102741512