Caching/session Question

I have a site which basically has a layout page displaying the 3 latest
news items down the left hand side of the page and the main content in
the center. The layout renders a partial to display the 3 latest news
items

_latestnews.rhtml
<% for article in @latestarticles %>
<a href=""><%= article.title %> </a><small>(<%=
article.created_at.to_s(:long) %>)</small>
<br/>
<% end %>
<%= link_to 'Read more recent news items', :action => 'news'%>&#187

layout.rhtml
The layout also contains a reference to the main content <%=
@content_for_layout %>.

controller
def home
@latestarticles = Article.get_latest_news()
end

When i click on the about_us page i get an error because the new page
doesnt have access to the 3 latest news items so for the about us page
to get it to work i have to the following

def about_us
@latestarticles = Article.get_latest_news()
end

and for the contact page
def contact
@latestarticles = Article.get_latest_news()
end

So for every page in the site i want the 3 latest news items displayed
down the left hand side but i dont want to have to include
@latestarticles = Article.get_latest_news() in every method when i show
a new page.

Whats the best way to manage this as im not really experienced with
caching, sessions and stuff like that.

Appreciate any advice?

In your app/controllers/application.rb file add the following: