i was wondering if anyone here has ever tried such metods like this.... http://free-playstation-3.blogspot.com/
As far as I know, the general consensus is that those methods work, but 99.9% of the time involve you signing up for things like credit cards or something similar. Far too much effort and personal information involved for me.
Don't bother. You'll have to fill out pages of registrations and you'll have to spend more then the price of a ps3 to actually get one. Usually this means signing up for a credit card that has to be charged with a certain amount before you're eligible for a ps3. You'll probably have to sign up for a few pay services as well, though they are usually a trial that is refundable. Even if you do all of that and use the credit card to buy things you would have purchased anyways(gas/food) you have to get proof from the various companies that you tried their "product". From what I understand this is usually not very easy. They make it as difficult as possible(while still legal) for you to claim your "prize". If you fail to complete one of the requirements you'll get nothing. edit: That being said there are people who do stuff like this to make a little bit of extra cash. If you've got a lot of free time and can afford to lose $500+ if something goes wrong it's actually possible to get "free" stuff.
Just don't post a link through to the site to improve your chances (the site will give you a special link that will credit your account with them for spamming Usenet/forums/myspace etc.) Ofc, I know Karsten would never dream of doing such a thing!