Sorry, it's we do some title stuff that is language dependent (the app still works in other languages, it just loses a small part of the magic). We are currently limited to countries that speak english (not just the US, but still limited, sadly). If you email me at webwright@gmail, I'll happily give you a free beta account. We'll attack other languages soon.

Does it support multiple timezones?

It should-- it actually uses the data from your native calendar and should behave the same with regard to timezones.