Hi hun and welcome!

We used GW with our DD to teach independent sleep and for NW too and it worked great for us. How are you resettling your DS now? Is he held, cuddled, fed to sleep, etc? This depends on how you tackle your first step really.
But basically you are looking at staying with your LO and then each night moving a step further away until you can just pop LO down in the cot and walk out. I started with putting DD down and then rubbing her back and using our sleepy phrase to calm her and until she fell asleep. I then just kept a hand on her back the next night until she was asleep. Then the next night just sat by the cot with no physical contact and from then on just moved further away each night. I always waited until she was asleep before I left the room, but once I was at the door the next night I just walked out and shut the door and she fell asleep.
There will be crying, but remember you are right there with your DS so he will not feel abandoned. He will be protesting at your new way of doing things. If things get too much you can always go back to the previous step, we had to do this once or twice. What we found worked best was no eye contact and being as boring as possible, so even when DD was stood up dropping dummies on my head I ignored her so she knew there was no chance of playing, she soon gave up and went to sleep!!

As for the NW, I would only go in if your DS is doing a cry (or scream) that escalates and says 'I need you now'. If not then wait and see if he can resettle himself. Have a look at this link (the GW part), it gives a bit more info on how to use GW...
http://babywhispererforums.com/index.php?topic=80750.0