What is the proper way to translate date string values?

Great module, thank you all!

Here is my question:
I have created a custom format "F Y" that displays the date like "March 2009" which is fine for English visitors.
Now the problem is that I would like to display it in the language of the user, for example in Dutch it would be "maart 2009".

Any ideas what would be the best way to do this?

Thanks,

Joep