You are very lucky, it seems that you can pick the one you like. In order to help you with this task here are some links, that should help you to make an informed decision.
The 2.2 release of OpenLinux for SPARC platform can be downloaded at
ftp://ftp.openlinux.org/pub/sparclinux/
You can join the mailing list by sending a mail to < majordomo@openlinux.org > with subscribe sparclinux in the body.
Debian GNU/Linux runs on SPARC platform; you can find a lot of informations about this port at the http://www.debian.org/ports/sparc/ webpage
You can join the mailing list by sending a mail to < debian-sparc-request@lists.debian.org > with subscribe as the subject.
Mandrake corporate server for SPARC can be downloaded at ftp://rpmfind.net/linux/Mandrake/iso/corporate-1.0/sparc
It consists of two ISOs, the core distribution is the *inst.iso one and the other one, *ext.iso, is the extension CD.
The latest RedHat Linux distriution is the 6.2; you can download it at ftp://rufus.w3.org/linux/redhat/redhat-6.2/sparc/ for example.
The mailing list can be joined by sending a mail at
< sparc-list-request@redhat.com > with subscribe as the subject.
At the time of this writting RedHat has announced its intention not to support anymore SPARC Linux in the future.
This distribution is unsupported at the time of this writting, and is not available as ISO. You can download it at ftp://ftp.slackware.com/pub/slackware/unsupported/protopkg/
The SuSe Linux 7.0 distribution is quite complete, you have 4 ISOs to download. You can grab it at the following URL: ftp://ftp.suse.com/pub/suse/sparc
You can join the mailing list by sending a blank mail to < suse-sparc-subscribe@suse.com >
TurboLinux Workstation 6.1 for intel ships with a SPARC developper release CD.
To install Linux on a SPARC based computer, should be strightforward if you follow the informations provided by your distribution.
To boot from a floppy drive you have to have an install image on a
floppy disk and to issue the boot floppy from the OpenBoot.
If your workstation does not have a CDROM or a floppy drive, you can always try
to perform a network installation using NFS as explained by
this French document:
http://www.linux-france.org/article/materiel/sparc-install/Sparc-netinstall.html
. Basicaly, you have to set up an NFS server and to boot your
workstation using the
boot net vmlinux nfsroot=192.168.52.12:/tmp
in order to access the image that is exported by the
192.168.52.12 workstation on the /tmp directory.