Why not download one of the big distro's such as Opensuse 10.3; the new Ubuntu; Red Hat's Fedora, or Mandriva's last work, and install that? The system will find your SPARC, and do the rest.
Nothing against Sun, by the way. Even though Sun has their own operating system, they support the Linux effort; and offer open source applications for Linux to boot (such as Open Office)! Thank God for Sun, and IBM for that matter!
Good luck in your efforts!