The alleged photos are of William and Kate swimming intimately, cuddling, and making out. According to a London newspaper The Sun, two men, John and George contacted them in an attempt to sell the photos.

http://www.hollywire.com/celebrity-scandal/prince-williams-intimate-photos-are-stolen/

Following the hack, screenshots of Mrs Palin’s messages, inbox, pictures and address book were posted to the Wikileaks whistle-blowing site. It is thought the attackers exploited the password resetting system of Yahoo’s e-mail service.

Details about Mrs Palin’s life pulled from public sources reportedly helped defeat security questions.
http://news.bbc.co.uk/1/hi/technology/7624809.stm