Currently the local software archive is offline. You can find binaries of the newsreader 'slrn' for various IRIX versions (among others) on this website.
SGI IRIX Freeware
This is the official freeware repository that was maintained by Silicon Graphics. It was last updated in May 2004. The packages are built for IRIX 6.5.
tcg software distribution
Tom G. Christensen has built this very nice collection of binary packages for IRIX 5.3 and IRIX 6.2. The tcg software distribution is still being maintained.