Sony has started the banning of thousands of PS3 hackers in Europe just moments ago and will most likely be spreading to the United States by nightfall. Looks like they are also sending Warning/Threatening E-Mails to everyone they currently have on their ban list.

"Sony's Banning E-Mail" by hatashi

Looks like Sony is also saying:

To avoid this, consumers must immediately cease use and remove all circumvention devices and delete all unauthorized or pirated software from their PlayStation 3 systems.

Source – PlayStation Official Blog

UPDATE: I have just received an E-Mail from Sony as-well so I can confirm it is real!

UPDATE: I have just call Sony Customer Service and they are saying they reason for the ban is the Call of Duty hacks and they are searching all updated PS3’s on 3.56 for the hacks (SO DELETE THEM) also he went on to say that if you call them back after your baned you can try to get unbanned, but I also must warn you they collect enough data most of the time to see if your lying.