SISAL is now free software, and may be obtained at http://kestrel.nmt.edu/raymond/sisal/sisal.html. Extensive documentation is included in this package.
NetCDF is also free software. Information on NetCDF may be obtained from the UNIDATA project of the University Corporation for Atmospheric Research at http://www.unidata.ucar.edu/Software.html.
An article on the GRI graphics package of Dan Kelley appeared in the July 2000 Linux Journal. This software may be retrieved from http://www.phys.ocean.dal.ca/~kelley/gri/.
Other functional and mostly functional languages which may be suitable for large-scale numerical programming are Haskell http://www.haskell.org/ and Objective Caml http://pauillac.inria.fr/ocaml/htmlman/.
Thanks to Niall Dalton for commenting on the manuscript of this article and to James McGraw for things too numerous to list.