Netscape, aka Netscape Communications Corporation, was a company that pioneered the commercial graphical Web browser. It has since been bought out by AOL. Still, the Netscape NavigatOr browser, is required by a lot of web pages. Is has been open sourced and became the base of FireFox. Many people think that rewriting the code base of Navigator made Netscape loose the browser wars.
You can download Netscape Navigator from ftp://ftp.netscape.com/pub/