At this time, creating a new user is locked. Get in touch with Nathan if you're interested.
How adding content works:
For starters, navigate through the Sections in the Main Page and click the Edit tab at the top of most pages to see how most of the content was added and formatted.
Adding text is a breeze. Just click the edit button of a page and then reference this MediaWiki help topic for formatting.
Click that link called "Upload file" in the left hand toolbox. Follow instructions to upload the file. Then when editing a page add the text [[Image:name.jpg]] and replace name.jpg with the name of the file you just uploaded.
- Note: current limitation is file must be less than 7MB
- Advanced formatting covered in MediaWiki Images Help.
Adding audio is tricky at this point so best to wait for it to be fixed.
Video can be linked to from other sites like google video and given the current 7MB limitation on file uploads, it's probably best to upload to a site like that and link to it. Here's some examples: