To do redirects in the Apache webserver you can of course use use mod_rewrite, but if you don't need a lot of complexity the simpler way to do it is to use mod_alias.
Documentation:
http://httpd.apache.org/docs/current/mod/mod_alias.html#redirect
Quick example - create a .htaccess and enter the following:
Redirect 301 /myblogs_olddirectory/ http://myblogsnewdomainname.wordpress.com/