Php is served up to the browser as html. The spiders "see" php pages as html like a browser. Try to "view source" on a php page and you'll see what I mean.

So to Google, there's no difference.

Awesome,

Thanks Kelly! I thought that when I went through the page source, but just wanted to check!!!

GoGetta

In my experience, there's no difference. What's
most important is what else do you do to make
Google love the pages, whether html or php,

[DELETED]

Yep, there's no difference really

It's just so that the actual web server (usually Apache) can know what file-type the file is, and then know whether it needs to do anything special (i.e. with HTML, just serve up the page; with PHP, parse the page, run the code, etc; with .asp; parse the ASP code; with a PDF, serve up the download)

So yeah, the page extension/file-type isn't anything to do with Google. It's just an 'instruction' for the web server and client's browser.