How can you file your previous years income tax online e file?

I have just now received my w-2's from previous years that the irs say i haven't filed them which is 2004-2008. and i would like to know how can i file them online e file rather than mail them in. I need help with as soon as possible because they are holding my 2009 taxes until i file these w-2's. And they said if i owe any taxes they will deduct them out of my 2009 taxes but when i called the irs they said i do not owe and taxes so do that mean i do not owe any taxes? well i know i have a offset which is child support and i know they amount and i know they will deduct that from my taxes but the ors said i don't owe them any taxes as of yet so do that mean i am clear once i file these and they deduct child support from my taxes? Can someone help me with this please. thanks so much