In-store displays for the iPhone are making their way into Apple and AT&T Stores nationwide. The AT&T display is white with a large screen displaying a demo, while the displays going into Apple Stores resemble giant iPhones, with a similar demo running on the unit’s display. NewsFactor has posted a report from a person claiming to be an iPhone tester. Balsu Thandu, the supposed tester, claims the handset is ready for launch. “For…