Remove URL Parameters and have it like folders (PHP)

Let's say I have a URL like...

http://www.example.com/i?id=123456789

Is there a way to make it look like the following instead?

http://www.example.com/i/123456789

I can send my website like that, but then it wont style it correctly because there is no index for 123456789; I wasn't sure if .htaccess can handle that.