AJAX load the_content from the_excerpt

I have a Page which lists Post titles and excerpts, like so:

<ul id="excerpts">
	<li>post 3: article about dogs</li>
	<li>post 2: article about cats</li>
	<li>post 1: article about llamas</li>
</ul>

I want to load the_content into a neighbouring element (not inline).
I would end up with something like the following, if Post 3 were clicked:

<ul id="excerpts">
	<li class="current">post 3: article about dogs</li>
	<li>post 2: article about cats</li>
	<li>post 1: article about llamas</li>
</ul>

<div id="post">
	<p>All about dogs</p>
</div>

Could anyone point me in the right direction to get this done? I checked out a bunch of plugins and articles but nothing seemed to match my requirements.