Computers can never replace Teachers, but a teacher who knows computers will certainly replace the one who doesn't !
I am a huge fan of free Classroom Information Management System. Now that most of the 2.0 tools are free, it can bring a revolution in countries that can afford to have a few computers and an internet connection in their class rooms. Google has a new Classroom Information Management System, Moodle has already made its mark and look at Khan's Academy. You can learn whatever you want for free. CALL (Computer Assisted Language Learning) is the future !