What is the best way to improve my typing skills?

Currently, my typing is slow and awkward. I only use my index and middle fingers to press the keys. I tried the standard touch-typing methods, but my ring fingers and pinkies were pretty ungainly. My speed is about 25-30 wpm, which suits me fine, but I'm applying for a job that requires at least 50 wpm or 5,000-8,000 keystrokes per hour (how does that work?). So what is the most effective way to reach that goal? Got any websites, software, or tricks?