AT&T has plans to move to an iPad-based Point of Sale system over the next two years, according to a new report. Citing unnamed sources as well as an AT&T spokesperson, 9to5Mac reports that the new system, which is being tested in AT&T’s Chicago “concept store”, will give employees the ability to perform all functions currently handled on behind-the-counter PCs on the iPad. These will include upgrade checks, account research,…