There are many companies who specialize in localizing web pages. Some have proprietary tools that produce multiple-language draft ("gist") machine translations (MT). All of them have many human translators (some in-house, some freelance) who finish the localizations. Among the world leaders are Berlitz GlobalNET, Lionbridge, Lernout & Houspie, and Bowne. But the biggest of them has less than a one percent share of the $10 billion world wide business of web localization and translation. Yahoo lists some 70 web translation services and tools. Multilingual magazine has a similar number of language translation vendors. The smaller companies generally do not have proprietary tools. They use industry-standard tools like Trados with translation memory (TM) that can be retained by their clients (in TMX format) so they are not captive to any one localization vendor.
Localisation Research Centre (LRC) is the information, educational, and research centre for the localisation industry in Ireland, arguable the world capital of Localization.