(This is probably the first of many requests for help I'll be making, as I begin learning the world of PHP - apologies for the possible stupid questions.)

I've installed a WP blog (twenty-ten theme), and on the main index page, I'd like the post listing to display ONLY the posts categorized as "news"; and to ignore any posts uncategorized or belonging to other categories. I don't want this to affect the page (page.php) template's normal display of any category. How do I do this?