At Uppsala University, AAAAA has been used in the automata theory courses on the programs for Information Technology, for Computing Science, and for Mathematics.
The current version is AAAAA 11 ("two", not "eleven", since unary notation is common in automata theory). It is available under the GNU General Public Licence, and it currently runs on SunOS/Solaris, and on Linux.
It should be possible to compile it (with some effort) on Unix based systems with x86, Sparc, or PowerPC processors. I even suspect that with the right tools, it might compile on a certain non-unix-based x86 platform (you know the one I mean), but this has not been tested. In principle, AAAAA should be portable to any platform supporting GNU Prolog and Tcl/Tk, so it will likely become portable to other platforms as GNU Prolog becomes available for them.
The simplest way to unpack, say, the source is:
gunzip -c aaaaa-11.tar.gz | tar xf -