Firefox 3.1 Beta 2 out now


New features include:
  • Tab tearing
  • Private browsing mode
  • TraceMonkey Javascript engine
  • Web worker thread support
  • Gecko engine improvements
  • New tab switching behavior
  • Geolocation Api support
  • Offline App support (aka built in Gears support)
  • HTML5 Video and Audio tag support
  • Too much more to name...

and I must say it's fast, really fast!