Did you make the same mistake I did, and update to Safari 4 when it was offered as a Software Update, then found some things didn't work any more, or you just plain don't like Safari 4? If so, here's how to revert back to Safari 3.2.3 on Mac OS X Leopard.
/Applications/Safari.app to the Trash, and rename the ~/Library/Safari folder (where ~ is your home folder, e.g. /Users/your-username) to something else (you're essentially making a backup here). It is important that you empty the Trash after doing this, as I found my 'new' Safari copied itself to my Trash folder.~/Library/Preferences/com.apple.Safari.plist and ~/Library/Preferences/com.apple.Safari.RSS.plist (if you have it - I didn't, but then I wasn't subscribed to any feeds) to something else (backups again - these files contain your bookmarks and RSS feeds so if you don't want to lose them, don't skip this step)/System/Library/Frameworks/WebKit.framework/Resources/Info.plist and replace all instances of the number 5530 with 5525. Please note: you may need to modify the file's permissions in order to be able to edit it. This can be done by right-clicking it, selecting Get Info, and modifying the permissions at the bottom - you need to give your username read and write access.There you go, just thought I would share :P
Edit: I have been asked for instructions for Mac OS X 10.4 (Tiger) - unfortunately, I don't have access to that version, but I'm told the instructions do work, except that the following modifications are to be made: