Using tables for text-alignment is getting a bit outdated. Preferred way to format HTML nowadays is using CSS.

There are a lot of usages for CSS - it's quite powerful - but I'll give you just a small example of how to keep all content of a page (or, the 'body' in HTML) away from the edge of the page.

Code:
<html>
<body style="margin: 20px;">
<p>This text is aligned at least 20 pixels
from the top, left, right and bottom from
the edge of the body.</p>
</body>
</html>
You'll find loads of information on CSS at the W3C Cascading Style Sheets Homepage at http://w3c.org/Style/CSS/