MVSP

MVSP is an inexpensive and easy to use program that performs a number of multivariate numerical analysis useful in many scientific fields.

It calculates three basic types of eigenanalysis ordinations: principal components, principal coordinates, and correspondence/detrended correspondence analysis.
It can also perform cluster analysis, with 23 different distance and similarity measures and seven clustering strategies.
MVSP is in use at hundreds of sites in 69 countries and its results have been published in numerous scientific journals, including Science and Nature.