By all appearances, hacker group Anonymous isn't too happy with the Department of Justice's move to take down file sharing site Megaupload today, because it's now claiming that it's knocked the DOJ's site off the internet — and for what it's worth, we're not able to load it. Likewise for Universal Music, one of the labels most directly opposed to Megaupload's existence, along with the RIAA's and MPAA's websites. Anonymous is apparently saying that there's "more to come," so it would seem that organizations that are in very public support of Megaupload's demise are going to be best served to have their IT departments on high alert this afternoon.