In recent days the iPhone blogs have been buzzing after noticing suspicious activity in the App Store. Over the weekend apps by developer Thuat Nguyen quickly rose to occupy 42 of 50 slots in the list of top apps in the Book category. Either he's a heck of a marketer or -- as bloggers suspected -- some shenanigans were at work. Then some people began reporting app purchases that they hadn't made, and the blog buzz grew. Now Apple has announced that indeed 400 iTunes accounts have been affected. But it's important to note that they said their servers had not been compromised. You can read more on Macworld and the New York Times. Apple has banned the developer and his apps, and recommends that you change your password. They're also bolstering their security.