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You're welcome, but please keep in mind that 301 redirects have an inherent loss of PageRank, even though it's quite small - no loss is better than some!

The better solution is to keep the .html extensions but tell Apache to parse them as though they were php. This is easily done in .htaccess:

AddType application/x-httpd-php .htm .html

I do this with pretty much all of my sites because real .html files are still served fine, and when there is php code it is executed as it would be with a .php file.