How can i upload Facebook application?

hey friends!
How can i make my own applications on Facebook??have you ever made any application on facebook?which one is that?

http://www.google.ca/search?q=how+can+I+create+a+facebook+application&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

Thanks anyway.