Lexol. The cleaner and the conditioner. I have been using them for years and really like how they clean and condition. You can find them at places like Pep Boys, Auto Zone and Trac Auto.
You asked me if my permission interior gets dirty easy. The answer is, yes. I have had my Z since September 09 and only have 4,500 miles on it. It's not my everyday driver. I have cleaned the seats twice. The bolstering on the driver's seat seems to get most of the dirt.