The Learn.Digilentinc site has some useful lessons, not only for beginners, but also for more advanced users of microcontrollers. For those of you who use chipKIT Pro products like chipKIT Pro MX7, Digilent put together the chipKIT Pro and I/O Control project to teach digital input and output using MPLAB X IDE and the MPLAB XC32++ Compiler. This project does require some basics skills/knowledge, like C or C++ programming, binary math and Boolean algebra, MPLAB X IDE basics, and a fundamental knowledge of electronics.
Happy Learning! :D