Facebook, myspace and twitter

Hello, this is my first project. I have recently launched a website that I would like to promote through facebook, myspace and twitter and in any other online platform I can find. I am fairly new at this so any help would be great. I already have a facebook account and have created a page within it for the website. I also have a myspace account, but it was created for my music although I do have about 1300 friends on it. And I have recently created a twitter account. The way I see it the more friends/followers the better. So if anyone can help along those lines it would be great.