API Allow Users
By default, user's don't have permission to use the API. To change this:
1) Click on Administration : Permissions
2) Click on the "Edit" link in the User Permissions column for the "*" user
3) Enable the "Use API" checkbox and click Submit Changes.
We have a little easter-egg: Go to any report and fill in the values so you get some graphs. Then edit the URL in the URL bar and add the text: &fmt=api
You'll see (Perl) API code to pull that report.