TOMS322 is a FORTRAN77 library which evaluates four standard cumulative density functions:
The text of many ACM TOMS algorithms is available online through ACM: http://www.acm.org/pubs/calgo or NETLIB: http://www.netlib.org/toms/index.html.
TOMS322 is available in a C version and a FORTRAN77 version.
DCDFLIB, a FORTRAN90 library which evaluates and inverts a number of statistical distributions.
GSL, a C++ library which includes many routines for evaluating probability distributions.
NORMAL, a FORTRAN90 library which samples the normal distribution.
PROB, a FORTRAN90 library which evaluates many probability density functions.
TEST_VALUES, a FORTRAN90 library which contains sample values for a number of distributions.
UNIFORM, a FORTRAN90 library which samples the uniform distribution.
You can go up one level to the FORTRAN77 source codes.