Customising pages wtih sidebars

My website uses a theme that contains a sidebar in each page. I would like to customise the pages so that I can have different sidebars or remove the sidebar completely. This is the code for the page template

<?php get_header(); ?>

<div id=”content” class=”grid_8″>

<?php if (have_posts()) : while (have_posts()) : the_post(); ?>
<div class=”post” id=”post-<?php the_ID(); ?>”>
<h2 class=”entry-title”><?php the_title(); ?></h2>
<div class=”entry”>
<?php the_content(‘<p class=”serif”>Read the rest of this page »</p>’); ?>

<?php wp_link_pages(array(‘before’ => ‘<p>Pages: ‘, ‘after’ => ‘</p>’, ‘next_or_number’ => ‘number’)); ?>

</div>
</div>
<?php endwhile; endif; ?>
<?php edit_post_link(‘Edit this entry.’, ‘<p>’, ‘</p>’); ?>
</div>

<?php get_sidebar(“page”); ?>

<?php get_footer(); ?>

any ideas where I can edit which page the template is applied to? and how to edit the sidebars?