Something really cool about the WordPress is the way you can create multiple page templates.
What does it mean?
For example you can create a template wich will show the page with no sidebar. Or you can create an other template with two sidebars.
Easy, you just need to create a file in yout theme folder called template-CustomName
Please notice you need to put this line I pasted above at the very top of the file. This Template Name will show in your admin panel when creating a Page.
Here a fully working example of a Full Width page template.