Inténtalo tú mismo - CSS Reference table

<!DOCTYPE html>
<html>
<head>
<style>
table.ex1 {
   border-collapse: separate;
   border-spacing: 10px;
}

table.ex2 {
   border-collapse: separate;
   border-spacing: 10px 50px;
}
</style>
</head>
<body>

<table class="ex1" border="1">
  <tr>
   <td>Peter</td>
   <td>Griffin</td>
  </tr>
  <tr>
   <td>Lois</td>
   <td>Griffin</td>
  </tr>
</table>
<br>

<table class="ex2" border="1">
  <tr>
   <td>Cleveland</td>
   <td>Brown</td>
  </tr>
  <tr>
   <td>Glenn</td>
   <td>Quagmire</td>
  </tr>
</table>

<p><b>Note:</b> IE8 supports the border-spacing
property if a !DOCTYPE is specified.</p>

</body>
</html>