A complete ANSI C Compiler for the PIC series with Rapid Application Development front end. Fully inclusive of all of the C Compiler environment and functionality. This is for the PICmicro MCU microcontroller family.
WIZ-C - PIC C Compiler Simulator and IDE
This has Drag and Drop component selection. Point and Click pin connections and direct parameter selection by drop down lists, check boxes and validated data entry. It also supports In-Circuit Debugging and also can transfer to MPLAB. (professional version). They have a free demo version too.
There is a optional library set to considerably ease USB development. Included components support timers, serial interfaces, I2C, LCD, 7 Seg displays, keypads, switches, port controls, many bus interfaces including IIC and Dallas iButton.
Learn to program a PIC micro with C using FED
This free manual will take you through the process of learning C from variables through constants to pointers and then structures and unions. Most of the examples are standalone and are as small as possible to enable the purpose and effect to be easily understood.