display single post on non-WP home page

I have WP 2.7 installed in a subfolder (/blog). My root home page is an HTML file, not a WP file but is set up so I can add php includes.

I would like to set up a blog category, call it homePosts, then add a widget to the home page that displays the most recent post in this category, or a summary of it.

How can I add a widget like this as a php include on the home page?

Thanks a bunch