Amongst all the iPhone 3G publicity, Apple quietly posted Safari 4.0 Preview to the Apple Developer Connection Website. It has scored 98% on the Acid 3 Test and requires Safari 3.1.1 to install. Safari 4 focuses on performance enhancements and this release is related to the upcoming Mac OS X Snow Leopard as Safari 4.0 will "begin laying down the foundation of the next iteration of the Mac OS X operating system". This preview has already appeared on the internet on certain torrent websites.
http://forum.insanelymac.com/index.php?showtopic=109832
http://forum.insanelymac.com/index.php?showtopic=109832