functions.php

<?php
/* I want the Posted On date to show, but not the author. */
function twentyten_posted_on() {
    printf( __( '<span class="%1$s">Posted on</span> %2$s <span class="meta-sep"></span> %3$s', 'twentyten' ),
        'meta-prep meta-prep-author',
        sprintf( '<a href="%1$s" title="%2$s" rel="bookmark"><span class="entry-date">%3$s</span></a>',
            get_permalink(),
            esc_attr( get_the_time() ),
            get_the_date()
        ),
        sprintf('')
    );
}