I am changing my site from html to php pages. I have read that to keep PR and google happy I need a 301 redirect. I have set this up (from old htm to php page, Same file name just extension changed). This works fine no problem, but my PR has dropped from PR2 to n/a (gray bar). Is this because Google needs to reindex the new php page and until that appens it will be PR-n/a? I have only carried out 301 on one page at the moment till I know what will happen. Any ideas? or have I done something wrong?