BY MADLEN READ -- For some cubicle monkeys, working from home sounds downright cushy: reclining in your PJs with a laptop propped up on your knees, a plate of freshly toasted Pop Tarts at your side, and ''The Price Is Right’’ twinkling in the background. But as the millions of telecommuters out there can tell you, it’s not like that at all. Not only do you need to be just as alert, productive and professional at home as you are in the office, you also have to make sure your boss knows you are. Here are some tips on how to telecommute effectively -- and how to ease your boss’s fears that your request to work from home is a sorry excuse to sleep in.