get_next_post custom post type
<?php
$prev_post = get_previous_post();
if($prev_post) {
$prev_title = strip_tags(str_replace('"', '', $prev_post->post_title));
echo "\t" . '<a rel="prev" href="' . get_permalink($prev_post->ID) . '" title="' . $prev_title. '" class=" ">« Previous post<br /><strong>"'. $prev_title . '"</strong></a>' . "\n";
}
$next_post = get_next_post();
if($next_post) {
$next_title = strip_tags(str_replace('"', '', $next_post->post_title));
echo "\t" . '<a rel="next" href="' . get_permalink($next_post->ID) . '" title="' . $next_title. '" class=" ">Next post »<br /><strong>"'. $next_title . '"</strong></a>' . "\n";
}
?>