Simple answer is No : You really don’t need an anti-virus software your iPhone, because iPhone runs a variant of OSX called iOS, which provides security mostly in itself. Also, iPhone apps run in a “sandbox” environment which has restricted access with other apps. Apple products is not nearly as vulnerable as Windows. But keep in mind, Jailbroken iPhones are vulnerable to worms, and are the ones most likely to get infected.
I’ve been using iPhone for nearly 2 years without any virus issues on my device. Google Android smartphone is more vulnerable to viruses than iPhone platform, according to antivirus software maker Trend Micro Inc.
If you still need some protection, you can use the Free Antivirus Trend Smart Surfing for iPhone and iPod Touch – If you attempt to access a bad or malicious URL, Smart Surfing is designed to block access to the URL and a notification will appear in the browser.