Need Best Solution

My old website is in PHP. now i redesign it in Adobe catalyst. So its page name extension are changed. old website pages are in .php. and new have .html.

My Issue is in search Engine. my many keywords are on good ranking position. so if i change the url name so ranking will be down. so i want to be redirect the old URL to new URL. But Its Page extension are different. so give me some better Idea for it.

If you are hosted on an Apache server, you can re-write the URLs—replacing .html with .php. Or your could set up redirects from the old pages to the new ones, but you might lose PR doing that (not sure). So perhaps URL rewriting is the best option. In that case, we’d move this thread to the Apache Configuration forum.