Alternate query_posts output

Hi,

How can I get the query_posts to alternate the output?

Ex; instead of this:

<h1>Header 1</h2>
<p>text</p>
<!-- end of post -->
<h1>Header 2</h2>
<p>text</p>
<!-- end of post -->
<h1>Header 2</h2>
<p>text</p>
<!-- end of post -->

I’d like to get this:

<h1>Header 1</h2>
<p>text</p>
<!-- end of post -->
<h1 class="hd2">Header 2</h2>
<p>text</p>
<!-- end of post -->
<h1>Header 2</h2>
<p>text</p>
<!-- end of post -->

You know what I mean??? So I can get the posts presented in an alternate way from each other…

Thanks for the help in advance.