I think it doesn't work on the 08, as it has only been a hidden feature on more recent hardware. Probably the same for your Mini, depending how old it is?
To my surprise, it works. I plugged in a Sony Music & talk Headset for iPhone to the front headphone port of my MP, and saw the new sound inputs show up in the Sound Preferences. Actually, TWO new inputs showed up (see pics)... I had to wiggle them a bit for the inputs to remain active, but both of them refer to the headset and work OK.
I tried them in skype and other sound recording apps, and they work fine - no need to pump the input volume all the way up. The sound quality of these mics is as any phone mic though.
Weird. We've got confirmed reports of it working in 2010 models, and I've seen with my own eyes it working on a 2009 (and the screenshots above). I don't understand why you can't get it working on a 2010 - you're trying to use the Apple iPhone headset plugged into the front jack, right?