I've got a site presently built using blogging platforms. I've got a requirement to drag the "latest publish" inside a category (magazine problem), to permit the most recent problem to become displayed within the sidebar of the Posterous blog template, in both an iframe or by other means.

What's the easiest method to accomplish this? Shall I write a custom PHP page which queries the database straight to output the outcomes which i want, after which display it within an iframe around the Posterous template? Or perhaps is there an simpler way to do this?

You can register a widget towards the sidebar or just add code the sidebar.php directly. Ultimately, all you do is creating a WP Query for that latest publish inside a category.