We stumbled upon some preview pictures of 1Password for the iPhone (see our WWDC chat with Agile Web Solutions), which were deleted almost as quickly as they surfaced on Dave Teare's photostream. Since we are, for the moment, playing by the rules of finders, keepers, we (gently) persuaded Dave to give us a little more info on what we were seeing.
It looks like the PIN field shown will allow for quick access to "less sensitive" information, such as your Digg or Flickr logins. For more secure sites, such as your bank account, the usual Master Password is implemented. Dave says they considered using gestures and other creative methods for unlocking, but in the end a "PIN feels more natural and is a well-understood concept, and you can't beat a real password for security."
Interesting to note is that the 1Password iPhone application will, itself, be a browser. Because of Apple's rules regarding "hacking" existing applications, they couldn't modify Safari to integrate 1Password. But Dave says that they're adding some "cool features" that will "make users not want to use Safari directly anyway." Personally, I'm more than willing to switch browsers for added security and convenience.
It looks like the 1Password team is going to miss the big App Store opening day, but they plan to be in there shortly after.