The chipKIT uC32 has been around a while, but Fábio Souza at Embarcados has just published a brand new Overview which is worth a look. The article is written in Portuguese; you should be able to use the "Translate" option in your browser to get the English version if needed.
Fábio's article borrows some diagrams from Digilent's excellent Resource Center, and also explains how to load chipKIT-core into the Arduino Boards Manager.
Thanks Fábio!
Note: The chipKIT uC32 is our full-featured, Uno-style board with 512K of Flash, 32K of RAM and 47 available I/O lines. It's fully compatible with Arduino IDE and MPLAB X IDE.