Alas, you have to change files on your site, but a) your worried about links to these pages, and b) you don’t want to lose the page rank associated with them. What do you do? Use a 301 redirect of course!
A 301 Redirect is a server side means of redirecting the request for a page to a new location. This can be an entire domain, directory, or specific file. There are several different ways of implementing a 301 Redirect and it depends on your flavor of webserver, Microsoft IIS, or Apache, and whether you have access to the web server settings or just your files.
Why do we care about the 301 Redirect? Well, for the two reasons mentioned above of course. In the process of optimizing sites for the search engines we often times have to change the file names and directory structures of a site. We’ll use a 301 redirect to make sure we don’t lose any page rank or break any links to these pages.
If you want to know more about how to do a 301 Redirect, here is some reading material for you: