Helpful links
MediaWiki Help page - http://www.mediawiki.org/wiki/Help:Contents
MediaWiki formatting cheat sheet for print out - http://meta.wikimedia.org/wiki/Help:Reference_card
Basic MediWiki page editing, formatting and creation
Create a inner wiki link on page with two brackets around the link [[link]]
Create an external link by typing in the fully qualified address and link text in single brackets </nowiki>[link text]</nowiki>
When you create the link, click it to create the page.
=== around text will create headlines to the number of = characters (It will also auto-generate a table of contents if you have multple levels)
bold text by using three feet marks '''
when you want to create a new line, enter two paragraph returns
bullet lists begin with an asterisk
- List item 1
- List item 2
- List item 3
Numbered lists begin with a #
- Item 1
- Item 2
- Item 3
Using an image as a link to a page:
http://support.uakron.edu/wiki/images/d/de/Oracle_db_sm.jpg
You can add a pre-formatted code-style box by starting a line with a space or using the <pre></pre> tags around your text.
Code Sample
Tables are a little trickier, using curly braces and pipes and stuff. See the Site of Sites page for an example.