This application will generate random passwords for you by using dictionary words and separator symbols. While all security experts agree that you should not use a single dictionary word due to guessability, using two or more combined makes your password much more secure than even a smaller password with uppercase, lowercase, and symbols. See also: http://xkcd.com/936/
This generator will take a number of random dictionary words, the value you specify in the first text box, above and stick them together. If you enable the checkbox for symbols, it will also add a separating symbol between each word, which increases the difficulty in someone's attempt to brute-force your password. The symbols were selected to be easy to get to on an iPhone, that is, they reside only on the first page of symbols without needing to shift to symbol mode, then shift to the alternate symbol mode.