Which file to edit?

I’m a novice at this and could be wrong, but I’m pretty sure you’ll want to enter the Theme Editor and modify Main Index Template and also Single Post. The latter is for when only a single post is displayed. You would obviously want to introduce the same formatting you’re doing for your Main Index Template.

Thanks for the reply Erik, but I think there is a little more to it than that.

In main index I have this code:

<h1><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></a></h1>
		<div class="descr"><?php the_time('F jS, Y') ?> by <?php the_author() ?><br /><br /></div>

Which is obviously the title, date and author. I would need to put a new div in next to the title and have it display the month and day.

Also there is no option within the design for “single post” or at least not in the theme I am using.

Download a theme that has a similar date gizmo and study how it was done. Apply it to your theme. It is too long a process to describe it here.

I just ripped that function out of a theme, check this one (stylesheet and index) to find out the trick.