BlackBerry time: When must you pay for employees’ off-duty PDA hours?

Hand-held devices, such as BlackBerrys, Trios, iPhones, etc., make it easy for workers to check e-mail and do work at any time of day. And your nonexempt, hourly workers may demand to be paid for that screen-time. So, when must your organization pay nonexempt employees for such off-the-clock work? There’s no clear-cut answer.