According to the IPv4 Address Report the anticipated date when the current policy regime concerning the distribution of IPv4 address is no longer relevant will be February 10, 2011.
Directly from the report:
The predictive exercise described here points to a time when the current address distribution mechanisms will no longer apply. The current address allocation policies used by the Regional Internet Registries (RIRs) are critically based on a continual supply of previously unused addresses being assigned to meet the needs of applicants. This is achieved by the RIRs continually drawing addresses from the unallocated address pool. At the point in time when the unallocated address pool is exhausted the current distribution mechanism for addresses as used by the address registries would appear to have reached a logical conclusion.
Does this mean that we need to move to IPv6 ASAP, or that internet growth will come to a halt on February 10th? Not really, but in order to satisfy the consumer and business needs for internet addressable devices I am sure we are going to see major IP allocation policy and network management changes until IPv6 is fully implemented. Base on current calculations there are under 35 million IPv4 addresses left for IANA to allocate to the RIRs.
World IPv6 Day
On 8 June, 2011, Google, Facebook, Yahoo!, Akamai and Limelight Networks will be amongst some of the major organizations that will offer their content over IPv6 for a 24-hour "test drive". The goal of the Test Drive Day is to motivate organizations across the industry – Internet service providers, hardware makers, operating system vendors and web companies – to prepare their services for IPv6 to ensure a successful transition as IPv4 addresses run out. Learn more about World IPv6 Day and how you can participate.