Interface builder's "Switch"

How do I refer to one of interface builder’s switches (also known as checkboxes) in my code?

Some thing along the lines of:

if theSwitch is selected then blah blah blah

I could find any info about them in the API reference that came with the Developer tools.

Anyone know how to do this?

I was just about to post something, but Jacques beat me to it.

See also: button