I agree that OpenID is not well explained to end users, either on the official website or on any of the websites of the major companies using it (that I have seen).
Maybe that is what motivated the people behind http://openidexplained.com/ - which is the best attempt I have come across. They use a Creative Commons licence, so you might be able to cut out the most relevant portions of the info and use it on your site. Or you could just link to them.
##Caveat##
Caveat
But that site doesn't cover everything, in my opinion. For decades now, end users have been encouraged to look after their passwords carefully - especially for important systems like their email account. With OpenID, the user is being asked to type in their Yahoo password (for example) in order to get access to some random website/app.
I think openidexplained.com does a good job of giving users a happy feeling that this is all hunky-dory. As the owner of that random website/app, this may meet your immediate needs. But out of social responsibility I think we should also be very clear what's so special about the situation the user is encountering that makes it hunky-dory. End users still must not just type in their Yahoo password whenever they are randomly asked for it.
The front page of openidexplained.com does say this:
When you type your username and password, make sure you're actually on the website you think you are (i.e., check the address).
But that is all it says. I would want to see this greatly elaborated with pictures and lots of words on the How do I log in page, but it's not, in the slightest.
