If you need to 301 re-direct one page to another in WordPress Blog you can start playing around with the .htaccess file adding in re-directs or you could use Redirection a WordPress plugin.
A simple install as ever with WordPress plugins, the re-directs are all managed in the manage section of the WordPress back end. Just add in the old URL and the new URL and your done.
There are further options to re-direct to a 404 page, to a random post, import from csv etc. So head over to the WordPress plugin page to download Redirection.