Marc Andreessen and Ben Horowitz have launched a new venture capital firm, Andreessen Horowitz, with an initial fund of $300 million.

The former Netscape duo announced the new firm on July 6 and said it "will fund technology startups with investments ranging from $50,000 and $50 million, working with the strongest entrepreneurs with the smartest ideas," according to a news release. "The firm draws on Andreessen's and Horowitz's extensive experience as successful engineers and company builders to create a new, modern venture capital firm designed to support the needs of today's entrepreneurs," said the release.

"Innovation is thriving despite the current economic climate," Andreessen said. "Ben and I are huge supporters of entrepreneurs and want to help turn today's sparks of brilliance into the next big thing."

"We see venture investing as a company-specific exercise," Horowitz said. "Therefore, we are looking for the best entrepreneurs and companies regardless of stage."

"Andreessen and Horowitz may also take board seats in their portfolio companies on a case-by-case basis," the release said.

Andreessen is perhaps "best known as co-author of Mosaic, the first widely used Web browser, later renamed Netscape Navigator, and co-founder of Netscape Communications," according to the release. "Andreessen's experience also includes his work as CTO of AOL, as well as chairman and co-founder of Web infrastructure company Loudcloud, later named Opsware ... and acquired by Hewlett-Packard."  Andreessen is "co-founder and general partner of Andreessen Horowitz ... He currently serves on the board of eBay and Facebook, and is chairman of the board of Ning, which he co-founded and launched in 2005."

Horowitz worked with Andreessen at Netscape, where he "ran several product divisions for Netscape, including Netscape's Director and Security product line, before becoming vice president and general manager of America Online's e-commerce platform division." Horowitz is "co-founder and general partner of Andreessen Horowitz ... Horowitz co-founded Loudcloud ... with Andreessen in 1999 and served as CEO of the company before it was acquired in 2007 by Hewlett-Packard. He was most recently vice president and general manager of Hewlett-Packard's Business Technology Organization Unit."

Building on the duo's "expertise and ... entrepreneurial track record, the firm will focus on investing in startups in the technology sector, including back-end infrastructure and consumer Internet startups. Andreessen Horowitz will look to invest in a broad range of innovative technology, from cloud computing, networking and enterprise applications to consumer Internet companies and social media businesses.

"Since 2004, Andreessen and Horowitz have served as angel investors for over 45 companies such as Aliph (Jawbone), ExtraHop, LinkedIn and Twitter." Andreessen Horowitz will be located in the heart of the IT venture capital world on Sand Hill Road in Menlo Park, Calif.

"We've had some time to test our investment approach and support great entrepreneurs," Andreessen said. "After years of angel investing, we decided to go pro and raise a fund."