How to show user information when user name is at the end of link

I have a website, say its

http://www.mywebsite.com

now I can show the user information if i do something like

http://mywebsite.com/user.php?name=John

i use php to query database to generate user information into an html page

But how can i do it like

http://www.mywbsite.com/john

do i create a page for each and every user i have ? or is there a better way