MVSP is an inexpensive and easy to use program that performs a number of multivariate numerical analyses useful in many scientific fields. It calculates three basic types of eigenanalysis ordinations: principal components, principal coordinates, and correspondence/detrended correspondence analyses.
Version 3 adds canonical correspondence analysis, a technique highly popular in ecological studies. 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 86 countries and its results have been published in numerous scientific journals, including Science and Nature.
You can get more detailed information or download a fully working demo version.