Inside your function for the click action use
$( "#tabs" ).tabs({ active: # });
Where # is replaced by the tab index you want to select.
Edit: change from selected to active, selected is deprecated
Simple jQuery solution - find the <a> element where href="x" and click it:
<a>
href="x"
$('a[href="#tabs-2"]').click();
Just to clarify in complete detail. This is what works with the current version of jQuery Ui
$( "#tabs" ).tabs( "option", "active", # );
where # is the index of the tab you want to make active.