changing language on fly

I'm looking for possibility to change language of my site on fly you may take a look at http://body-builders.org and see yourself - now when I press language button I can get to the main page in sertain language but what I want it to do is if I'm for example at 'Links' page and click on language button (or text link) I get to 'Links' page on different language. It can be reached by changing one charachter in the name of the file Let's say I'm on links page in English: http://www.body-builders.org/index.php?links=1 I want to go to russian page which would be: http://www.body-builders.org/indexr.php?links=1 So I want do make a script to do this change Youri <>< <>< <>< <>< God is our provider ><> ><> ><> ><> http://www.body-builders.org/