This is something I've been planning for a long time. I started working on it last year and got side-tracked on making some other improvements. I'm planning to get back to the translation effort this year.
Support for different languages has been added to version 10.0. A beta is available if anyone would like to help validate the translations or get an early look. The beta can be downloaded here:
http://www.vueminder.com/forums/phpBB3/viewtopic.php?f=5&t=908
Anyone that helps complete a translation will receive a free license!