Month, Day etc. names in other languages other than English

Hi all,

I was wondering if it was possible to internationalize the constant
month and day names, used by DateTime class (for example), in to
something other than English? Using gettext I am able to
internationalize most of the application. But in some cases where I
take something like a DateTime and represent it with a string, I see
the English names for days and months.

Cheers,
Diego