If you're interested in the Wikidata project but you can't directly contribute in terms of code, you can help with some research: http://kendra.org.uk/ http://dev1.kendra.org.uk/
These people are doing something very similar, i.e. building free-form databases using a wiki-like model (see the second link).
We need to know: 1) What exactly are Kendra's capabilities? 2) Is there potential for cooperation between Kendra and Wikimedia?
If you want to research this, please respond to this message so that there's no needless duplication of effort. You could use http://meta.wikimedia.org/wiki/Kendra_evaluation to chronicle your findings.
Regards,
Erik