Starting With Adsense - Build a Free Website

So you want to build a website? Now you have two options. Either you go in for a free hosting and some subdomain offered by the hosting website. Or you invest a little money and buy yourself a domain and hosting.
At this juncture, IF, you want to make it big and are sure that you will get high traffic, then I would recommend the latter. But, for starters, you might want to go in for free hosting and after that you might as well upgrade your hosting account, if you think you're getting good money and traffic. So let's proceed from the beginning :

First, let us discuss the 'free option' :
1) Hosting : First you need to get yourself reliable, well established and recommended hosting so that your website doesn't stay down all the time. To check out a few reliable free web hosts, I would recommend : Free Web Hosting Directory . Here you will find a list of many free web hosts. Choose any of these and sign up with them.( Be sure to read the reviews of the hosting you opt for)
2) Now that you have a free hosting, and along with that, a subdomain. You might want to install any Blog Script ( Wordpress ) , or CMS Script ( Joomla , Drupal ). These scripts will allow you to easily create a website with little effort. I wouldn't go into the details of these scripts. Please learn how to use them yourself.
3) Now, that you have a website, add some content and launch the website. Now comes the hard part : Apply for Adsense. After you submit your application, you might have to wait for a week or two for their decision on approval/rejection.
4) Publicize your website by posting articles in Social Bookmarking Sites ( Digg , Reddit ). Submit your site to any of the tons of Listing Directories (Search google for 'website directory' )

If you want to BUY a domain and a hosting (for professional and serious people) :
Build a Website With domain and Paid Hosting