Add Custom User Meta Field

<?php
function add_custom_user_meta_field($user) {
    ?>
    <h3>Custom Meta Field</h3>
    <table class="form-table">
        <tr>
            <th><label for="custom_meta">Custom Meta</label></th>
            <td>
                <input type="text" name="custom_meta" id="custom_meta" value="<?php echo esc_attr(get_the_author_meta('custom_meta', $user->ID)); ?>" class="regular-text" />
                <br />
                <span class="description">Enter your custom meta value here.</span>
            </td>
        </tr>
    </table>
    <?php
}
add_action('show_user_profile', 'add_custom_user_meta_field');
add_action('edit_user_profile', 'add_custom_user_meta_field');

function save_custom_user_meta_field($user_id) {
    if (!current_user_can('edit_user', $user_id)) {
        return false;
    }
    update_usermeta($user_id, 'custom_meta', $_POST['custom_meta']);
}
add_action('personal_options_update', 'save_custom_user_meta_field');
add_action('edit_user_profile_update', 'save_custom_user_meta_field');
?>