We all have tons and tons of usernames, passwords, and credit card numbers that we need to remember. Luckily, OS X has a great utility, that is under appreciated, commonly called the Keychain that'll store all of that info for you securely.
For a single user Keychain is great, but what if you need to share these passwords amongst a group like in an IT shop? Nirlog.com has a great roundup
of several Mac only and cross platform apps that'll help you out.