Using ZdMultiLang seems to be the most competent solution for multi language installations. But if you choose to show a static page instead of the default index.php of posts for the main page ZdMultiLang doesn't seems to be able to handle it. The main page simply shows the posts listed as an index instead of using the settings for a static page? Bug?
http://www.thewebpage.com - shows the static page chosen i the dashboard.
http://www.thewebpage.com/en/ - shows the main page as an index of posts instead of the chosen static page. (/en/ being the permalink for English)