You are interested and want to contribute? Just give it a try: anyone can edit and add translations and definitions. In order to be able to modify existing data, you will need to create an account and insert the Babel template on your user page, so that we know which languages you are familiar with. You will then be given edit rights (or please request them). If you have any question go to the discussion page or on IRC and you'll find people who can give answers.
You know PHP, Java, SQL and want to help with developing? The OmegaWiki software is an extension to the MediaWiki software and is available under the GPL license. The Development
page explains how to install your own OmegaWiki. If you need help, please contact Kipcool