Here you can find some of the software I wrote. You are welcome to it, as long as you leave in the copyright notices. Also, the software comes as is, with no guarantees whatsoever.
A collection of matlab routines to do clustering. It is not very extensive ! For now, only k-means clustering is implemented and a slow agglomerative procedure. As of version 2, it contains EM of Gaussian mixtures with automatic selection of the number of components. However, while I think the code is correct, the code has not been exercised a whole lot since my group and I switched to working in ML. Hence, use at your own risk ! If you find bugs and you have a fix, I'll gladly incorporate the fix in the code.
To get a feel for what is here, take a look at kmeansdemo and at EMintro, which produced the figures in my TR on Expectation-Maximization
Frank Dellaert's Homepage