Multilingual site

I would like to add another language to my existing site, however as I will be targeting another market with the new language, the structure of the new language website will be a bit different (more simplified) than the existing one in english.

How would I best go about it? So at the moment I have http://www.mysite.com and then when the user clicks on the spanish language flag they will be taken to the spanish version of the site which will obviously have all text in spanish but will also look a bit different than the english version. Therefore there is an issue of both translation (which i could handle with wpml) and website structure (not sure how to handle this).

Maybe I could create an extra site with the network feature of wp 3, or is this unnecessary. Thanks!