I was able to install 1Password on my iPod touch and (after a few false starts) synchronize my 600+ desktop entries to the device, but unfortunately now 1Password coughs and dies on the touch when launched. I did manage to get some setup screenshots before things went south, including the desktop-side code entry to pair the device and the computer, so feel free to peruse the gallery -- once we have a bit more time (and I've thinned out my sync list) we'll give the long-awaited utility the full review it deserves.
1Password for iPhone requires 1Password 2.8.1 on the Mac for synchronization. For a limited time, 1Password for iPhone can be downloaded free of charge.
Update: Agile has let it be known that version 1.2 of 1Password has already been sent in to the App Store, so you should be seeing the upgrade as soon as Apple gets it loaded (which may be a little while).