Workstations running operating systems based in UNIX, and most variants of X Windows should come with the appropriate fonts built in, and the newest versions of Netscape (4.x) should work if configured properly for your machine.
A summary of some of the free Japanese software available for UNIX machines, plus links to download most of them can be found at the University of Washington's Japanese Computing on UNIX and X Windows page.
For information on both the browsers and links to download, see: