Should I be using a 301 redirect?

[SlowMove]

I'm not sure why, but Google is spidering all my directories without using "index.html" in the URLs. Am I going to suffer a duplicate content penalty if it spiders both "www.site.com/directory/" and "www.site.com/directory/index.html"?

If so, what's the best way to handle it?

If this is a problem, what other possiblities are there for it to find the same page under other URLs? Do I need to include some sort of redirects with regular expressions to prevent it from seeing "www.site.com/file.html" and "www.site.com/file.html?foo" as the duplicate pages?

[Mike_Levin]

A Found 302 redirect is par for the course with Goolge, and every other hit on your Website to a URL that ends without a filename. It's what webservers do when you use no filename, and it literally redirects the browser to the default (usually index.html or default.htm). So, when you construct your links in your website (usually part of your navigation), you are actually causing this by linking to www.domain.com/dir instead of www.domain.com/dir/index.html. But there's no penalty that I ever noticed, so don't worry.