The GNU Scientific Library (GSL) is a collection of routines for numerical
computing. The routines are written from scratch by the GSL team in ANSI C,
and are meant to present a modern Applications Programming Interface (API)
for C programmers, while allowing wrappers to be written for very high level
languages. 

GSL is currently in developers release, for people who want to work on the
library itself. When the library is complete and fully tested it will be
announced for general use. 

WWW: http://sourceware.cygnus.com/gsl/