Apple's Pages on iPad by default gives you the word count of your document in a little box at the bottom of the screen when you enable the feature in the settings menu. But you can also see the character, page and paragraph count instead.
To change word count to one of these, just enable word count from the 'wrench symbol', Settings first. Then, tap the black word count box at the bottom of the screen once to see these other 'hidden' options.
This was tested on Pages 1.5 (not on iPhone), which is an iOS 5 exclusive version.
