The \n and \t are still there, but they do nothing in html. Use a string replace function or nl2br();
$string = nl2br($string); //turns \n into <BR>\n
The tabs are tricky because the only way to do that in html is with <blockquote>, but then you have to put it before and after the paragraph.
<pre> might be a better option...quick and easy...
---John Holmes...