LulzSec is a group people that hack websites and such stuff. They have broken in to Sony's servers and taken personal information. Username, passwords, email adresses and other info is being posted on the internet. Minecraft may be next. Here's a few of their twitter posts.
LulzSec wrote: Just sunk the Minecraft login server, looks like their website also got hit from overkill: minecraft.net not even firing at the site.
LulzSec wrote: Eve Online, Escapist Magazine and Minecraft are all down. We let Fin Fisher back up (30 minute temporary fire request completed!)
LulzSec wrote: Minecraft servers 100% down, website is up. You can watch their trailer video and everything! :D #TitanicTakeoverTuesday
LulzSec wrote: If you're mad about Minecraft, we'd love to laugh at you over the phone. Call 614-LULZSEC for your chance to reach Pierre Dubois! :3
Here's their twitter: twitter.com/#!/LulzSec
and website: lulzsecurity.com