Pimp My Safari
   Safari plugins, Applescripts, bookmarklets and news. For those wanting to customize Safari the way that Firefox can be customized.
   http://pimpmysafari.com/

PithHelmet
   An extended site preferences and ad blocking plugin for Apple's Safari browser. The basic purpose of the plugin is to allow the user to control the blocking of ad images, Flash, Shockwave or midi loops.
   http://culater.net/software/PithHelmet/PithHelmet.php

PocketMac Safari Scrapbook
   Advanced web browsing history recorder and search utility (for Safari only).
   http://www.pocketmac.net/products/pmsafariscrapbook/safari.html

Safari
   Apple's browser. Requires Mac OS X 10.2 or later.
   http://www.apple.com/macosx/features/safari/

SafariSorter
   Sorts Safari bookmarks. Several convenient features.
   http://sheepsystems.com/SafariSorter/SafariSorter.html

Scifience
   Software for Safari including a download optimizer, a debugging tool activator, and an "Aquifier" to change the appearance of Safari. Donationware.
   http://www.scifience.net/

Scriptable Applications: Safari
   Safari-specific applescripts.
   http://www.apple.com/applescript/safari/

Surfin' Safari
   Blog from David Hyatt, one of the engineers working on creating and updating Safari.
   http://webkit.org/blog/

pozytron.com: AcidSearch
   A search enhancement for Safari. It adds unlimited "Search Channels" to the Google search field. Channels can be customized in a nearly infinite variety of ways. Many features.
   http://www.pozytron.com/acidsearch