Download of Screen Sieve
With Screen Sieve you can search the through the active window for characters, words and sentences. Simply activate Screen Sieve by using a shortcut and enter the phrase you are searching for. The program then highlights all matching parts on the screen.
Screen Sieve uses the Accessibility API of Mac OS X that the window to be searched (the program) must also support. Many applications, such as Safari and Mac Mail, can be searched very simple and intuitive.