Brian from teho Labs wrote a tutorial on how to setup serial UART communication on various microcontrollers. UART code examples for the Arduino, ATMEGA168, MSP430, STM32, and LM3S are provided.
From his nice writeup it is easy to see why the Arduino is so popular. Being a library based platform, only two lines of code are needed to setup UART on a Arduino. Considerably more typing is required to get other microcontrollers working.
Via the forum.