Irregardless IS a real word
read the wikipedia article. It's been around for over 100 years, is ingrained in our culture and language, and brings up 678,000 search hits on google.
People say that it's superfluous and meaningless to add the "ir" prefix to "regardless", since its already a dismissive word. However in reality it enhances the expression of the speaker or author. No longer are you restricted to a mere "pah, regardless, whatever", the ir in irregardless adds an extra dimension of derision and je m'en fiche to your statement.
For example, "irregardless of what self-appointed grammer guardians would have you think, history recognises a truly great word, gargantuan, titanic; epic in it's glorious awesomeness."
Update: that was in 2007. in 2013 it now brings up 1.6 million results. Although many of those are haters like Ollie's dad, ranting that it isn't a real word. which it clearly is.
People who are right: Me, Ollie. This guy
People who are wrong: Ollie's Dad, Jonny. 2000+ idiots on facebook
i hope that helps to clear everything up.
irregardless.co.uk is part of the deadbad empire.
this page was written in notepad2 cos it rocks.