According to Slashdot:

http://it.slashdot.org/it/06/10/29/1859218.shtml

An anonymous reader writes, "Netcraft has discovered that the social networking site MySpace appears to have been compromised by phishers who have presented a spoof login form on the main site. This modified login form submits the victim's username and password to a remote server hosted in France." From the article: "The hackers have engineered a fake login form on MySpace's own web site. Netcraft has notified MySpace of the issue, although it currently remains live. Because the fraudulent login page is hosted on MySpace's own servers and does not exhibit any signs of external content, such as cross-site scripting or open redirects, it is convincing and even security-conscious users are at risk of becoming victims. The attack is launched from a profile page, where the username is login_home_index_html, and uses specially-crafted HTML in order to hide the genuine MySpace content from the page and instead display its own login form."

A July 16, 2006 Washington Post Article writes about why Phishing Attacks are being done on Social Networking sites
http://www.washingtonpost.com/wp-dyn/content/article/2006/07/15/AR2006071500119.html