Require Approval For Joomla Web Link

In Joomla! 1.5.3
Change line 105 of components/com_weblinks/views/weblink/view.html.php
from $weblink->approved = 1;
to $weblink->approved = 0;

To remove the published option from the web links form:
comment out lines 59 - 68 of components/com_weblinks/views/weblink/tmpl/form.php
change from

to

source: http://docs.joomla.org/Require_Approval_For_Web_Link