I’m a vim user myself, and I was very happy to find that the guys at Akita On Rails had put together a small vim helper that allows you to jump directly to the APIdock page of the given Rails keyword. You can find it from their Github dotfiles commit.
Keep these contributions coming. :)
UPDATE: There’re now emacs bindings available as well.
UPDATE 2: One of our own guys also implemented a TextMate command.

Nice one! Now that for TextMate would be awesome!!
With Mr. Marques permission, I uploaded a Vim plugin-ized version of this to Vim.org: http://www.vim.org/scripts/script.php?script_id=2571
You can also check it out on GitHub: http://github.com/mileszs/apidock.vim/tree/master
I hope some folks find it useful!