from Sony Imagesoft was folded into SCEA in July 1995, with most affected employees transferred from Santa Monica to Foster City. On August 7, 1995, Race unexpectedly resigned and was named CEO of Spectrum HoloByte three days later. He was replaced by Sony Electronics veteran Martin Homlish. This proved to be the beginning of a run of exceptional managerial turnover, with SCEA going through four presidents in a single year. The PS console was released in the United States on September 9, 1995. As part of a worldwide restructuring at the beginning of 1997, SCEA and Sony Computer Entertainment Europe (SCEE) were both re-established as wholly owned subsidiaries of SCEI. The launch of the second PS console, the PlayStation 2 was released in Japan on March 4, 2000, and the U.S. on October 26, 2000. On July 1, 2002, chairman of SCEI, Shigeo Maruyama, was replaced by Tamotsu Iba as chairman. Jack Tretton and Phil Harrison were also promoted to senior vice presidents of SCE. The PlayStation Portable (PSP) was SCEI's first foray into the small handheld console market. Its development was first announced during SCE's E3 conference in 2003, and it was officially unveiled during their E3 conference on May 11, 2004. The system was released in Japan on December 12, 2004, in North America on March 24, 2005, and in Europe and Australia on September 1, 2005. Creation of SCE Worldwide Studios, acquisitions, and restructure (2005–2011) On September 14, 2005, SCEI formed SCE Worldwide Studios, a single internal entity to oversee all wholly-owned development studios within SCEI. It became responsible for the creative and strategic direction of development and production of all computer entertainment software by all SCEI-owned studios—all software is produced exclusively for the PS family of consoles. Shuhei Yoshida was named as president of Worldwide Studios on May 16, 2008, replacing Kazuo Hirai, who was serving interim after Harrison left the company in early 2008. On December 8, 2005, video game developer Guerrilla Games, developers of the Killzone series, was acquired by Sony Computer Entertainment as part of Worldwide Studios. On January 24, 2006, video game developer Zipper Interactive, developers of the Socom series, was acquired by Sony Computer Entertainment as part of Worldwide Studios. In March 2006, Sony announced the online network for its forthcoming PlayStation 3 (PS3) system at the 2006 PlayStation Business Briefing meeting in Tokyo, Japan, tentatively named "PlayStation Network Platform" and