Here's another update for whoever wants to test:
http://dl.dropbox.com/u/12134784/CSSU/worldclock
Post bugs here please.

BTW: The alarm library has alarm_event_set_sound, that is supossed to set a custom ringtone for each alarm. But it doesn't work...

The source is here: https://gitorious.org/osso-clock
You're welcome to contribute

PS: My english sucks, I know...