http://www.freecomicbookday.com/fcbd_global.asp
There's also a store locator for those who are interested.
DC's comic this year deals with Blackest Night so I suggest if you go to see if they have DC Universe 0, which is only 50 cents, but it was like a snapshot of most of DC's major storylines last year... Final Crisis, RIP, Amazons Attack and the whole Green Lantern war of colors.