I'm not sure how you call it, but could anyone help me with this problem:
Is there a way to set a .php file to a directory.

Example:
I have 2 files in the same directory: onepage.php and secondpage.php. If I want to visit index.php I would go to ..../onepage.php (lets say: www.stackoverflow.com/onepage.php). Then, if I want to visit the second page I would go to www.stackoverflow.com/secondpage.php. However, is there a way to make it so it's visible as www.stackoverflow.com/secondpage?

Also, if I take the same example, and let's say I have a $\_GET at my secondpage.php, is there also a way to do www.stackoverflow.com/secondpage/($\_GET value) ? 

Thanks.