The info below is taken from the developer's blog.
After some lengthy Agile board room meetings, dry erase boards filled to the brim with really, really important diagrams, back-to-back PowerPoint Keynote presentations, and vigorous focus group testing, we decided how 1Password for iPad pricing will work by flipping a coin. Ok, just kidding about the coin thing. And the dry erase boards.
1Password for iPad will cost just $6.99. We built this version specifically for iPad owners who do not plan on owning an iPhone or iPod touch. It has a gorgeous interface that was designed exclusively for the iPad, which you can get an early peek at in our previous iPad posts.
1Password Pro will contain both iPad and iPhone versions for users who own both devices. Once Apple approves the update we submitted along with our iPad-only version, 1Password Pro will sell for $14.99, though this upgrade is free to current owners (right now 1Password Pro is a steal for $8.99!). 1Password Pro already includes some great features over the standard iPhone version, like Folders and support for copying multiple items to Safari. In future updates, 1Password Pro will gain even more exclusive features, such as wireless sync via MobileMe and WebDAV, as well as Favorites for easy access to frequently used items.
1Password standard will sell for $6.99 from now on and will not gain the iPad interface.