The organization responsible for allocating these numbers is the Internet Assigned Numbers Authority, which delegates blocks of IP addresses to five regional registries. It is IANA that allocated its last available IP address blocks to the regional authorities on Thursday.
The regional registries, in turn, allocate their IP addresses to companies, ISPs and telcos. With no new blocks coming from IANA, they will start to run out of their address pools over the next several years, starting with the Asia-Pacific authority, known as APNIC, probably in mid-2011.
As regional authorities run out of available IP addresses, their clients will too. That means ISPs and companies will have difficulty assigning unique IP addresses to their customers, employees and servers as soon as this year, starting in Asia.
Code:
http://www.wired.com/epicenter/2011/02/internet-addresses/