We're really just starting to get OSQA (http://www.osqa.net) to a point where we can implement some of the new features and improvements which we hope will make it most useful.

We invite you all to share your ideas about what you want and need in a Q&A community at http://meta.osqa.net or to submit bugs and feature requests directly into our tracker at http://jira.osqa.net.

The best hands down is OSQA the english CNPROG fork, written in python. See http://osqa.net and, for an example of the site actually running: http://meta.osqa.net.

The developers for OSQA are currently building a tool to import a StackExchange dump. Two thumbs up for simple migration!

There is also a promising one in ruby called Shapado.

For a comprehensive list, evaluating project health and pointing at demos, check out this StackExchange answer: http://meta.stackoverflow.com/questions/2267/stack-overflow-...

Thank you!

There's also a Ruby on Rails clone called Shapado: http://gitorious.org/shapado (a running example here: http://shapado.com/)

That's the best one =)