Does ICC provide any official calculator or software to calculate scores according to Duckworth-Lewis Method?
There are any number of unofficial calculator apps available on the web - a simple google search will give you links.
The official software for calculating DLS (Duckworth-Lewis-Stern) scores is called Coda, and to my knowledge is only available through the cricketing boards in each country. Normally it is supplied to clubs or teams by the governing body of the competitions they control, with instructions for its' consistent use.
From Cricinfo post "The Duckworth-Lewis Method (1999)":
Although there is a computer programme, CODA, that is used by official first class and international scorers to carry out all calculations of D/L targets, unfortunately, CODA is no longer available for purchase by the general public
And from The Duckworth-Lewis Method (2001):
There is a computer program CODA which carries out all calculations of D/L targets and provides many features besides. This program, which is now owned by ICC, is used by official scorers around the world. It is currently unavailable for purchase by the general public.
So to answer your question: Yes, the ICC do provide an official piece of software, but it's not generally available.