If you use a category cloud, that would do the trick, or just put the category widget that comes already with 2.5, and put it in your sidebar. When people click the category (drop down menu) , they will only get posts in that category. Also, most premium themes (paid) have the categories listed across the top of the page, and when clicked show all posts in that category.
Assuming you are using WordPress, put this in your page: <ul> <?php $posts = get_posts('numberposts=XXX&order=ASC&orderby=post_title&category=YYY'); ?> <?php foreach( $posts as $post ) : setup_postdata( $post ); ?> <li><a href="<?php the_permalink() ?>" title="Link to <?php the_title(); ?>"><?php the_title(); ?></a></li> <?php endforeach; ?> </ul> Code (markup): Replace the XXX with the number of posts you want listed and the YYY with the ID of the category you want posts from.