iPhoneDevWiki uses the same wiki markup as Wikipedia and other wikis that run on the MediaWiki software.
See Wikipedia's formatting cheatsheet for how to do general wiki markup (italics, bold, links, images, and so on).
For help making tables, see MediaWiki's table formatting page.
Syntax highlighting
You can make code snippets nicely syntax-highlighted using these tags:
<source lang=objc> NSObject *anObject = [[NSObject alloc] init]; </source>
Which will produce an output that looks like the following:
NSObject *anObject = [[NSObject alloc] init];
This wiki uses GeSHi as the syntax highlighter. It supports many languages such as bash, c, cpp, text.
To add a helpful navigation box to the bottom of an article documenting a class, you can use tags like these:
{{occlass|library=SpringBoard.app|navbox=1}}
{{occlass|library=CoreFoundation.framework|navbox=1}}