Silentum PasswordGen is an excellent password generator tool if you need passwords for email clients, message boards, IM programs, or any other protected pages. It has various options, including choosing whether to use lowercase/uppercase letters, numbers, symbols, and spaces, in any combination you desire. Its character limits extend between 5 and 50, and you can generate 1 to 5 passwords at a time. You can use this for your own personal use, or place it on your site to allow visitors to generate their own passwords. It runs entirely on a single PHP file, and doesn't require any MySQL.