Why are all of my pages out of alignment? (TwentyTen theme help!)

I am designing a website (located at https://www.educationstrategygroup.org) and when I click on certain pages, the alignment of the page changes. For example, from the home page, click on “Contact Us” and you can see that the whole page moves to the right a little bit. Does anyone know how I can fix this problem? It’s never happened to me before with other sites. Then again, this is my first wordpress site, so I don’t know if it is wordpress specific or something wrong with my code. Please help!