Not been to it,but thought I'd try out the 'magic' website to see if it was on there. It is down as a scheduled ancient monument, just says er, standing stone. So it's old at least.

That godawful millenium stone is on the other side of the motorway, right next to where you park your car to go to Mayburgh henge (though I heard they actually wanted the stone IN the henge, yeah Right)