1Password is one of my most-used iOS apps, since I need it to log in to any site which requires a password.
Since the introduction of 1Password on iOS, Agile has provided a bookmarklet which will open 1Password and then search for the current domain. That helps the fact that 1Password can't be fully integrated with Safari on iOS. Unfortunately the bookmarklet stopped working in iOS 5.
According to the company's blog, Agile has discontinued the bookmarklet and won't be updating it. They are working on "something better coming up for the future." They went on to add that they want to make 1Password's own integrated browser "more usable as "a Safari replacement, or rather partial replacement."
While I will reserve judgment until I see it, I have serious reservations about this plan. I have used iCab Mobile on the iPad for over a year. iCab is a superior browser to Safari, but it is still difficult to use instead of Safari because iOS doesn't allow you to change the default browser. It's hard to imagine that 1Password's integrated browser will be better than iCab.
Fortunately, two 1Password users, Kevin Yank and Brendan Averett, have created a new Look Up in 1Password bookmarklet which is compatible with iOS 5. You can either copy that link, or use this:
I have successfully tested it on iOS 5 and 1Password Pro (with both Safari and iCab).