Correct format for dates in letters in Polish?

Hi. could anyone tell me the correct format for the date in letters i.e. Nominative or Genitive?

It would be in the format of :
05 November 2011

Thanks,
vincent

genetive - 8 listopada 2011 - but most often we give dates numerically 2011-11-08

Thanks Gumishu

And that would be on semi formal letters as well?

I would use the form with the month's name for less formal letter but it does not matter that much

day,month,year.

8.XI.2011

Or is that like REALLY old fashioned?

after roman numerals there shouldn't be any dot, at least I was taught so :)

so, 8. XI 2011.

True but it's better to start with day, not year. Makes more sense in everyday situations.