Earlier today, ICANN distributed the last batch of its remaining IPv4 addresses to the world's five Regional Internet Registries, the organizations that manage IP addresses in different regions. These Registries will begin assigning the final IPv4 addresses within their regions until they run out completely, which could come as soon as early 2012.
IPv4 has been the primary communication protocol for the Internet for more than 20 years, so this final allocation marks the end of an era, to the extent the brief history of the Internet can be categorized this way--IPv6--is essential to the continued growth of the open Internet. IPv6 will expand Internet address space to 128 bits, making room for approximately 340 trillion addresses.
Microsoft announced that "On June 8, we'll enable world-wide IPv6 connectivity to Bing.com, for the purposes of a one-day test. Consumers with IPv6 Internet capabilities will automatically access this new method of connectivity. This necessitates both a device that supports IPv6 (like a Windows 7 PC), and support from your Internet provider.
IPv4 traffic will continue to connect to Bing without any change. In fact, most Bing users won't even notice that this transition is occurring."
Microsoft, Google and other tech companies have been working behind the scenes for years to outline a clear path to the next gen IPv6. Although a complete migration will take years, hopeful the vast majority of people will never notice the transition.