As TMO’s illustrious Mr. Landau pointed out, all you have to do in Lion is hold down the letter you’d like to accent, and what Apple refers to as the character picker appears.
When you see that, go ahead and select the correct option with your mouse or by hitting the number underneath the one you want. You can also use the arrow keys to highlight your choice and press enter.
Great! Awesome! Fantabulous! Now how do we turn it off? Apple doesn’t provide an easy way to do it, but if we get a little tricksy, we can work around that. It turns out that there’s a preference file in your user’s Library > Preferences folder called ApplePressAndHoldEnabled.plist. To switch the setting within that file, open the Terminal program (it’s within Applications > Utilities) and type the following exactly, then hit enter:
defaults write -g ApplePressAndHoldEnabled -bool FALSE
After that, you’ll need to log out and in again or reboot to force the change to take effect. To switch the preference back to showing you the character picker when you hold a letter down, repeat the above command in Terminal, but replace “FALSE” with “TRUE.”
I love the new features in Lion! And I most especially love them when I can turn them off.