The Mozilla browser apparently works (at least to a certain extent) with the GNU Lesstif library; this is probably your best bet for a Netscape-like browser on Linux/m68k (after all, Mozilla is a stripped-down version of what will be Netscape Communicator 5.0). See http://www.mozilla.org/. The current development version of Debian includes a Mozilla package.
Note that there is a LinuxPPC version of Netscape available (it's actually called the "MkLinux" version), which apparently works with Linux/APUS.