Apple today released Safari 4 at the WWDC 2009. Apple calls Safari 4 the world's fastest and most innovative web browser.
Safari 4 will be available for Mac and Windows PCs and introduced as a beta in February of this year, Safari 4 features the Nitro engine which runs JavaScript up to 4.5 times faster than Safari 3.

Apple says that Safari 4 makes browsing more intuitive and enjoyable with innovative features, such as Top Sites, Full History Search and Cover Flow, and support for modern web standards like HTML 5 and advanced CSS Effects.

Safari 4 is available for both Mac OS X and Windows as a free download at www.apple.com/safari. Safari 4 for Mac OS X requires Mac OS X Leopard(R) v10.5.7 or Mac OS X Tiger(R) v10.4.11 and Security Update 2009-002, a minimum 256MB of memory and is designed to run on any Intel-based Mac or a Mac with a PowerPC G5, G4 or G3 processor and built-in FireWire(R). Safari 4 for Windows requires Windows XP SP2 or Windows Vista, a minimum 256MB of memory and a system with at least a 500 MHz Intel Pentium processor.