For addition to .htaccess:
# Redirect old site pages via mod_alias.
Redirect 301 /the/old/url.html http://example.com/the/new/url.html
Redirect 301 /another/old/url.html http://example.com/another/new/url.html
See Apache Module mod_alias for mod_alias docs and HTTP/1.1: Status Code Definitions for a list of HTTP status codes.
