g1smd - 1:10 am on Feb 2, 2009 (gmt 0)

In most cases, there's no need for one rule per URL.

If the URL structure has been properly designed, then a small number of patterns can be used, each matching hundreds or even thousands of URLs and programatically redirecting to the correct new format.

If that's not an option, then use a redirect script that captures all of the requests for old URLs, looks up the new URL in a table, or database, and then issues the appropriate redirect HEADER data back to the browser.