Developer SplashData has provided features that make this application very attractive. For example, there are Mac and Windows desktop apps that sync wirelessly with the iPhone version, so you can do a lot of your editing and data entry from the desktop instead of using the iPhone's keyboard. Data is protected by 256-bit Blowfish encryption, and there's a built-in generator for creating unguessable passwords.
SplashID is available now from the App Store (click opens iTunes) for $9.95 and the desktop version is available at the SplashData website for $19.99. There's also a 30-day free trial available.
Two of SplashData's other mobile titles, SplashMoney and SplashShopper, are also now available for iPhone and iPod touch.