I don't know of any perl modules for this specifically. Probably the most portable way is to use tables:

<div class="math">
    <table class="fraction" cellpadding="0" cellspacing="0" >
    <tr>
    <td align="center" class="numerator"><i>Aa</i><sub>0</sub><i>qp</i
+>
    </td></tr>
    <tr>
    <td align="center" class="divider">---------
    </td></tr>
    <tr>
    <td align="center" class="denominator"><i>b</i><sup>2</sup>
    </td></tr>
</table>
</div>
[download]

which looks like