The best and quickest way to chill wine and champagne is to put it in a bucket of ice water. This method of chilling wine will drop the temperature of the wine one degree per minute. The proper temperature for serving white wine is 48-52º. Thus, figure out the temperature of the room in which the wine has been stored, choose a desired temperature from the given range above and subtract it from the room temperature. The resulting number is how many minutes you will need to chill your bottle of wine. If you don't believe us, get out your thermometer, open the bottle of wine before you chill it, measure its temperature, leave the thermometer in the bottle while it chills and watch the temperature drop one degree per minute.
Another note on chilled wine, it is always best to buy unchilled wine as keeping wine chilled too long in any refrigerator changes the flavor of the wine.