I have done it in the past...not sure how long they kept...we used them so quickly! As to how you serve it....I used a rocks glass 2 oz of scotch and the coffee cubes! 8) or took hot coffee and poured it over the coffee cubes so's not to dilute the coffee!
I ahev been making iced coffee cubes for about 3 years now- I usualy use a cube tray that has a cover to avoid picking up any of the freezer tastes/ odors.