This is the source code for the pronounceable generator from the password generator page. The alpha-numeric password generator is very simple and doesn’t do anything complicated besides generate a random MD5 hash and truncate the output.
The pronounceable password generator is more complex. It is originally from this Java source, which I converted over to C#. Pronounceable passwords are intended to be safe from dictionary attacks but comprise of words very similar to English words, making them memorable. Adding several numbers and a non-alphanumeric digit is recommended to strengthen them even further.