More information on what you are doing would help as you would need no code to do this in a post just use the align from the editor menu, where are the two images coming from?
The text and images need to be inside a class, the class needs to be float: left; and position: relative
The twenty eleven theme has three classes alignleft, aligncenter and alignright.
As a guide if I wanted to add the post thumbnail to the excerpt and float this right, the text will float left and the image right
<div class="entry-summary">
<?php
if( has_post_thumbnail()) : ?>
<div class="alignright">
<?php the_post_thumbnail('thumbnail'); ?>
</div>
<?php endif; ?>
<?php the_excerpt(); ?>
</div><!-- .entry-summary -->
HTH
David
