Just pick up a password manager. Try Keepass…
http://keepass.info/features.html
or Roboform
They’re a couple of the best… and both have free versions. Both encrypt all your passwords into a secure database, and — shazam — all you have to remember is one *single* password to get access to all your others. Both can even help you dream up passwords, if you’re fresh out of great password ideas.
I’ve been using and recommending Roboform for over five years, currently have passwords for almost 300 websites. I have both the standard and portable versions. I really appreciate good tools and this is a very good one.
Another good choice is http://www.lastpass.com. It is available as a firefox, IExplorer and Chrome plugin. It’s completely free.
Another ABSOLUTELY marvellous resource for Mac users:
1Password by http://agilewebsolutions.com/ It is phenomenal and can be used from any computer (Mac or PC) ‘on the go’. You can design HUGE and STRONG passwords for each of your sites and log in places and the programme will remember it for you easily. One password will unlock all the others for YOU only.
Mac users: check it out!