I wanted to use Clickpass in an webapp that I've been developing, as I like the idea of a simpler way of handling OpenID. However, when I peeked at the developer documentation, I got this:
"Clickpass is being reworked. Please, don't develop against the current Clickpass implementation."
Are there any decent alternatives to Clickpass, or should I just work a plain-old OpenID library into my site instead?
I would make that decision based on what libraries exist for your web framework, and just how customizable you need your SSO solution.
If you need something simple up and running as quickly as possible, use one of the existing providers - a common choice is Janrain Engage (previously RPXNow).
On the other hand, if you need to customize your login behavior and use advanced features, just roll your own using any existing OpenID lib.