This is a great bit of code that does exactly what it says. I used it to replace lsqcurvefit as I no longer have the optimisation toolbox.
I would suggest that the author also considers using additional examples, as the ones given are very complicated to understand if you come from a very different field. However, after a little search I found this by the author, which I found much more useful:
It tells you how to use the function to fit a curve to some data. This should be easily modified for fitting other functions/data etc.