CountChar
A little utility counting the characters in a text field
CountChar is a little utility that can count the number of characters in a given string. Very simple to use. You paste your string into the top text field and CountChar immediately gives you the number of characters in that string. You can additionally perform operations on the text extracted from the other application.
Note: you may have to log out or force the Finder to quit to see the new option. You obviously have to quit any application that are running when you force quit the Finder. CountChar must be installed in one of the "blessed" application directories, which are /Applications (for computer-wide installation), /Network/Applications (for network-wide use) or /Users/[your username]/Applications (for specific user installations).
CountChar is now exclusively available from the Mac App Store here.