The easiest way would just be to make use of HTML's title attribute inside each of the panel's DIV, for example:
Code:
<div id="mygallery" class="stepcarousel">
<div class="belt">
<div class="panel" title="this is panel 1's description">
<img src="http://i30.tinypic.com/531q3n.jpg" />
</div>
<div class="panel" title="this is panel 2's description">
<img src="http://i29.tinypic.com/xp3hns.jpg" />
</div>
<div class="panel">
<img src="http://i26.tinypic.com/11l7ls0.jpg" />
</div>
<div class="panel">
<img src="http://i31.tinypic.com/119w28m.jpg" />
</div>
<div class="panel">
<img src="http://i27.tinypic.com/34fcrxz.jpg" />
</div>
</div>
</div>
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