OpenID provider for my users

Hi guys,

I’m confused… I want to be able to be an openID provider for my blogusers.
I host multiple sites/blogs and people have to have an account on all these blogs to post, edit, author (and more). They have to login to each blog seperate.
My idea is to create one blog/site/wordpressdomain where people can register (and login) and this will be an identity/login provider for all the other sites. Kinda like google, yahoo, wordpress.com and more but in this case for mydomain.nl
Any ideas how to create this?