Who? Singaporean high school cheerleader.
Real? The tape circulates, but I have no idea if the girl is really named Tammy Nyp.
Wikipedia has the best account of the Tammy Nyp sex tape:
The Tammy sex video scandal was a scandal in Singapore involving a sex video first circulated in mid-February 2006 that turned into an Internet phenomenon. The incident began when a cheerleader and student from Nanyang Polytechnic (NYP), known only as Tammy, apparently had her mobile phone stolen by an enemy, and a 10-minute video stored in her phone involving oral sex and intercourse with her boyfriend was uploaded on the Internet.
The video was initially spread obscurely via instant messaging, email and blogs, but eventually made it to the front pages of national newspapers. Shortly after, the video gained international notoriety as many people curiously began searching for it online under the keyword Tammy Nyp, causing the scandal to make it to the first five places in Technorati’s top search terms for almost two weeks.
The instant blog I Love Tammy Nyp posted several local newspaper stories as scanned jpegs.
The Tammy Nyp sex tape has typical cellphone video flaws: tiny frame size, pixelly image and jerky framerate. Also, they set the camera down sideways for several minutes. Nonetheless, the sex is pretty hot and imaginative.