Check out the wp_link_pages function

<?php $args = array(
    \'before\'           => \'<p>\' . __(\'Pages:\'),
    \'after\'            => \'</p>\',
    \'link_before\'      => \'\',
    \'link_after\'       => \'\',
    \'next_or_number\'   => \'number\',
    \'nextpagelink\'     => __(\'Next page\'),
    \'previouspagelink\' => __(\'Previous page\'),
    \'pagelink\'         => \'%\',
    \'echo\'             => 1
);

wp_link_pages( $args );  ?>