HEAT SENSING IPHONE - FLIR Systems Inc., the leading maker of professional imagers that "see" heat, is bringing out its first consumer-level product: a jacket for the iPhone that contains a heat camera. Temperature differences show up in different colors on the screen of the phone. For instance, you can set it to show hotter things in yellow, medium-hot in red and cold in purple. It can discern temperature differences as small as one tenth of a degree. The FLIR One will cost $349, which compares with $995 and up for FLIR's professional thermal imagers. Practical applications for the camera include identifying leaky insulation and moisture. Fun applications include spotting wildlife, high-tech hide-and-seek, and crazy party pictures. ("Everyone was so hot!")