Preprocess a specific table
Unlike forms, specific invocations of theme functions don't have identifiers associated with them, so there's no mechanism like hook_form_FORM_ID_alter() that you can use unfortunately.

I can only find one call to theme('table') in the nodequeue module so I think you're talking about the theme_nodequeue_arrange_subqueue_form_table() function. 

Luckily enough, this function assigns a unique id to each table (which believe me isn't always the case), so at least you can target it in a preprocess function:

function MYMODULE_preprocess_table(&amp;$variables) {
  if (isset($variables['attributes']['id']) &amp;&amp; $variables['attributes']['id'] == 'the_id') {
    // Alter the table
  }
}


As the theme_nodequeue_arrange_subqueue_form_table() function actually renders the table to a string (it has to, being that it's a theme function itself), I don't think there's any other way to do this.

The other (more long-winded way) would be to implement your own version of the entire theme_nodequeue_arrange_subqueue_form_table() function, copying the code from the original and just changing what you need to.