Forbes reports that former Gartner research director Michael Gartenberg has joined Apple. While his exact position at Apple hasn't been revealed, Gartenberg is said to be working under Apple marketing chief Phil Schiller.This isn’t Gartenberg’s first time jumping into one of the technology companies he tracks — though his last foray lasted less than a month. In Feb. 2007, he joined Microsoft as an “enthusiastic evangelist,” a job he described at the time as being designed to “engage and work with enthusiasts and other influencers and show them all the cool stuff that Microsoft is doing. In short, it’s our job to act as the bridge between Microsoft and end users.” But he left