Displaying category specific posts in a wordpress blog is easy. Inside theme folder the you will find “index.php” and “sidebar.php” templates, you have to put a query_posts functions which refer to specific category ID numbers from your database. Example:
<?php query_posts('showposts=1&cat=4'); ?>
You will need to change them to reflect the ID numbers in your own database. They can be found in your control panel under Manage->Categories.
Result will be the recent posts from the category no.4