Unless you can do something like a link that points to something like the Google translation tool (for a crude translation) OR you will have to maintain two websites for the respective languages and simply have a link on one or all of the pages to go from English to Spanish. If you want the menus, etc to all be sync'd then you'll probably end up with a second Office Live web.
Hope this helps,
Chris
http://www.helpitcrashedagain.com