Here is a great Cydia add-on for international travelers. International Locations for Siri allows Siri to perform local searches outside of the U.S.. While Siri can speak several languages, and is also available in other countries, location based services are currently only available in the U.S..
I obviously can't test the tweak without leaving the country, but the $0.99 investment may be worth the risk to some frequent travelers. The add-on is available for download via the BigBoss repo. If you do not already have AssistantExtensions it will be installed when you download the tweak.