Multilingual homepage I am currently in the proses of making my first multilingual Drupal site. Using the i18n module I have been able to get separate menus and their respective pages. 

My problem is that the content on the home page, with the theme that I'm using is created/edited via a page.tpl.php file. Do I need to duplicate this file and have one for each language? If so how to I go about this?

This is the site: http://www.lac-de-montbel.com/

Thanks in advance.
No, you don't need to duplicate file, just go to /admin/config/regional/translate/translate and search for what you want to translate.

To be able to translate strings or variables from custom page.tpl.php file, all of them in the file need to be translatable, ie. to be in t() function, so if you can't find words that are from some custom .tpl.php file, make sure that particular string or variable in the file is translatable (in form like I mention).

For more information about using function t() look this.