Starting off, make today the last day you say "irregardless" however. It my greatest fear that so many people are going to start saying the word incorrectly that Webster will add the incorrect usage to the dictionary and then all hope will be lost. All. Hope. Lost.
Below are several sites that have lists of the wrongs and rights so you can get your mouth in shape.
10 Common Words You May Be Mispronouncing
Words Can Make You Look Stupid