Mythryl is currently supported only on 32-bit x86 Linux. (Volunteer ports to other platforms are welcome!) Your best bet is Debian "unstable" (the development platform) or failing that Debian derivatives such as Ubuntu or gNewSense but any 32-bit x86 Linux should serve without undue trouble.
Release 3.0.2 version
mythryl7.110.58-dist-2009-09-07-11.47.45.tar.bz2 is the latest:
Click HERE to download it.
The downloaded tarball is a tar archive compressed using bzip2. On most systems you can uncompress it by doing
myprompt% tar -xjf mythryl7.110.58-dist-2009-09-07-11.47.45.tar.bz2
If your system does not use GNU tar, you may need to uncompress and unpack separately:
Either way, you will wind up with amyprompt% bunzip2 mythryl7.110.58-dist-2009-09-07-11.47.45.tar.bz2 myprompt% tar -xf mythryl7.110.58-dist-2009-09-07-11.47.45.tar
mythryl7.110.58 directory
containing the system source code plus seed binaries (needed because
the compiler is self-compiling).
The mythryl7.110.58/README file documents the rest of the
installation procedure.
For general information about Mythryl, see the online documentation.