If your goal is to get muscle definition then creatine is absolutely not the way to go. Creatine binds water to your muscle fibers and will make them look thicker but you'll be bloated and not "ripped"
also with creatine, you do have to take it every day or it will leave your body quickly and you'll receive no benefit from it. since it binds to water in your body, if you dont keep replenishing the creatine you will urinate it away.
creatine is also meant to be cycled. that means you use it for maybe three months and then go off of it for three months. it can stress you kidneys so I find this to be particularly important.
personally I find creatine effective, but many people claim it doesnt work for them (I think they dont take it on off days though) but to be honest its only worth taking if you find your regular diet and exercise regimen have hit a wall and you're no longer making gains. then take the creatine for a month or more to break through that plateau
...and I can't stress this enough. drink tons of water if you do take it. I've read lots of stories about wrestlers who take it while cutting water weight dying or otherwise injuring their heart.
so anyway on to your questions =)
1. the creatine molecule itself provides energy to your muscles during anaerobic use (think weight lifting, and not running) so chances are in your off days you won't get your muscles into that anaerobic regime. So, for all intents and purposes it will do nothing on your days off. but other benefits have been found wth creatine. check this out http://news.bbc.co.uk/2/hi/health/3145223.stm
2. Yes you do have to lift weights to get the intended benefit. creatine doesn't put mass on you on its own (unless you count the water bloating) all it does is get you more bang for your buck in the gym. it is still your hard work that will get you anywhere. The major definig factor in the effectiveness of creatine is how consistent you are in dosing. so you still have to take it on days off.
sorry, no free ride =)