I want to code the Metaphone 3 algorithm myself. Is there a description? I know the source code is available for sale but that is not what I am looking for.
Since the author (Lawrence Philips) decided to commercialize the algorithm itself it is more than likely that you will not find description. The good place to ask would be the mailing list: https://lists.sourceforge.net/lists/listinfo/aspell-metaphone
but you can also checkout source code (i.e. the code comments) in order to understand how algorithm works: http://code.google.com/p/google-refine/source/browse/trunk/main/src/com/google/refine/clustering/binning/Metaphone3.java?r=2029