Как-то так:
<script src="http://code.jquery.com/jquery-2.1.1.min.js"></script>
<body>
<table>
<tr>
<td class="info">
<span class="info_but">Кнопка 1</span>
<div class="info_cont">Ла-ла-ла</div>
</td>
</tr>
<tr>
<td class="info">
<span class="info_but">Кнопка 2</span>
<div class="info_cont">Ла-ла-ла</div>
</td>
</tr>
<tr>
<td class="info">
<span class="info_but">Кнопка 3</span>
<div class="info_cont">Ла-ла-ла</div>
</td>
</tr>
</table>
<script>
$('.info_but').mouseover(function() {
$(this).next().show();
});
$('.info_but').mouseout(function() {
$(this).next().hide();
});
</script>
</body>