It is still under construction and content may change. Do not rely on the information on this page.
What is autotest?
Autotest is "a framework for automated testing". It gives us a way to run automated tests and collect results. For more information, see their wiki: http://autotest.kernel.org/
How is it used in Fedora?
We're currently using it as the test harness for AutoQA. It handles the dirty work of getting code onto test machines, running it, and holding all the results.
Currently there is no public autotest instance. The QA team has been working on packaging autotest for use in the Fedora infrastructure.
The AutoQA project is starting out by using it to automate some existing tests (like repoclosure from 
yum-utils
How do I write a test for autotest?
Start by writing some test code in whatever language(s) you feel comfortable with. Don't even worry about autotest or AutoQA until you have a functioning test. Once you do, see Writing AutoQA Tests for more info.
How do I set up my own autotest server?
Docs in progress - see this trac ticket