HTML Prototype:

<div class="tabcontainer">
<ul class="selector">
	<li class="tab"><a href="#tab1">tab 1</a></li>
	<li class="tab"><a href="#tab2">tab 2</a></li>
	<li class="tab"><a href="#tab3">tab 3</a></li>
</ul>
<div class="clear"></div>
<div id="tab1" class="tabcontent">content</div>
<div id="tab2" class="tabcontent">goes</div>
<div id="tab3" class="tabcontent">here</div>
</div>

Attempted function api:

function defaulttab( $atts, $content = null ) {
return '<div class="tabcontainer">' . do_shortcode($content) . '</div>';
}

add_shortcode('tab', 'defaulttab');

function defaulttabs( $atts, $content = null ) {
extract( shortcode_atts( array(
'title' => '',
'tab' => '1',
), $atts ) );
return '<ul class="selector">
<li class="tab"><a href="#tab' . $tab . '">' . $title . '</a></li>
</ul>
<div class="clear"></div>
<div id="tab' . $tab . '" class="tabcontent">' . $content . '</div>';
}

add_shortcode('tabs', 'defaulttabs');