How do I get cd's to autorun on my mac?

In the interest of security, autorun is not possible on OSX. You can master media to autorun, but OSX doesn't allow it.

Others may have the same question as you. Post here if this information answered your question; post also if you have any additional questions.

If, by "autorun" you mean automatically run software from the CD, as in some versions of Windows, then Poikkeus has already answered -- can't be done, and it's a good thing, too.

If, however, you mean, automatically execute some action when an optical disk is inserted, then you can do that with System Preferences > CDs & DVDs. For instance, you can set iTunes to launch automatically when you insert an audio CD.