I've read a lot about openid in recent few days and found out it's not as easy on a standard web space.
I've only follow available in the web space:
Is it possible to setup openid or which one?
I found what I'm looking for here http://www.janrain.com/openid-enabled
You can install OpenID that system as it is running CGI and PHP, both of which are supported by OpenID.
You could also get ahold of your hosting provider and ask them to install Ruby, Python, or C# on the system and enable it for you.
most provides which act as an openID-Provider, server different APIs in different languages, for example Twitter. So you need only one of these languages to use openID. Btw,. there's a nice graph at Google which describes the openID-process.
If you want to act as openID-Provider I don't know the requirements ^^