Updated

Google Inc. (GOOG) and computer maker Sun Microsystems Inc. (SUNW) plan Tuesday to announce a "collaborative effort" in Silicon Valley.

Sun issued a media advisory Monday saying that the two companies will hold a press conference hosted by Sun Chief Executive Scott McNealy (search) and Google Chief Executive Eric Schmidt (search) at the Computer History Museum in Mountain View, California.

A Sun spokesman confirmed the press conference, but declined to elaborate on the announcement. A Google spokesperson was not immediately available to comment.

Schmidt, who was once chief executive of network software maker Novell Inc., also led the development of the Java programming language at Santa Clara, Calif.-based Sun Microsystems, where it was invented.

Schmidt also helped to define Sun's software strategy and served as the company's chief technology officer.

Google, the leader in Internet search, has been on somewhat of a tear in Silicon Valley and neighboring San Francisco in recent weeks.

On Friday, marking its biggest step into the wireless communications market to date, Google said it has proposed to provide free high-speed wireless Internet service across the city of San Francisco.

The Web search company said it had responded to a request for information by San Francisco, which has a population of more than 700,000, to test local Internet services via Wi-Fi, the short-range wireless technology built into most new laptop computers.

Also, Mountain View, Calif.-based Google said on Sept. 28 it would partner with U.S. space agency NASA on space research and would build a new campus at the agency's research center in the heart of Silicon Valley.