Refer to http://www.italki.com/question/280050

지금 means now as in a specific point in time Eg: 지금 2시이예요. 이제 means now in a slightly more general sense Eg: 이제 밥 먹고 있어요. But as far as I understand they are interchangable in many cases This is different from 요즘 which means now-a-days Eg: 요즘 서울에 살고 있어요. http://koreanwithjohn.blogspot.kr/2012/04/difference-between-and.html http://www.italki.com/question/55829 https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=what%20is%20the%20difference%20between%20%EC%A7%80%EA%B8%88%20and%20%EC%9D%B4%EC%A0%9C