Each page should provide an easy way to get to other pages. Make sure each page has a clickable company logo at the top or some way to get to the main page. You want to make the site easy to navigate.
You can't assume that all visitors land on the main home page first. Those linking in from search engines and other sites frequently arrive at your site on a minor page below the main one. Many users prefer to use "search" to find things on a site. It can be a good idea to include a search option on all pages.
Nielsen, Jakob (1997) Search and You May Find, Alertbox, July 15, 1997.