>and click on the "1 Available" link
For the benefit of anyone else trying this, it doesn't do anything in Firefox, you need to find your long-forgotten copy of Internet Explorer.
As you could easily see if you inspect the HTML that you're generating as source HTML, rather than just looking it in the browser (which is a *really* bad way of debugging), you're generating an invisible "<a href=""><br/>" in the PM column for every time that isn't a PM time. You could solve that by moving the xsl:if to the outermost level of the template rule. But I would tackle this quite differently:
<td valign="top" bgcolor="#FFFF99">
<xsl:apply-templates select="Time[contains(@slot, 'am')]"/>
</td>
<td valign="top" bgcolor="#CCFFFF">
<xsl:apply-templates select="Time[contains(@slot, 'pm')]"/>
</td>
then
<xsl:template match="Time">
<a class="Item" href="{@href}">
<xsl:value-of select="@slot"/>
</a>
<br/>
</xsl:template>
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference