A nice resource to create strong passwords is Wolfram Alpha search engine. This site will generate a random password for you with a full description about the time it would take to crack the password and other interesting security information.
Wolfram Alpha (styled Wolfram|Alpha) is an answer engine developed by Wolfram Research. It is an online service that answers factual queries directly by computing the answer from structured data, rather than providing a list of documents or web pages that might contain the answer as a search engine would [Wikipedia]
How to generate random passwords :
Nice online tool to generate safe passwords without install any third party software.
Link : Wolfram Alpha
About password security testing , read also :
Test your password : Strength Test
Test your password : How Secure Is My Password
Test your password : Microsoft password checker
Test your password : The Password Meter
Nice information and link shared regarding password strength. Thanks.