It's the same command text you mentioned in your opening post, except that you exchange "google" for "apple". So, use this command text:
Code:
http://maps.apple.com/maps?q={text}
By the way, Google Maps are still far better than Apple Maps for where I live. I hope Marvin will soon give us the option to set up an
unlimited amount of custom menu buttons -- all of those I set up are taken by dictionaries (there's not enough buttons for dictionaries themselves...), so it's too bad I can't use some of these other intriguing custom commands in Marvin.