I recently updated my own toolchain to the newest versions of all involved software:

1. Arduino 1.0.6
2. Teensyduino 1.20 plugin installed into Arduino 1.0.6
3. Arduino 1.5.8
4. Eclipse Arduino IDE 2.4

The instructions still work as written, however,  for users of the Teensy 3.x boards  the boards txt file had to be updated to allow the selections for the Teensy 3.1 under clocking for low power applications. The overlocking speeds are commented out, but are easy to enable by editing the boards.txt.