The MPLAB series of devices are programmers and debuggers for Microchip PIC and dsPIC microcontrollers, developed by Microchip Technology.
The ICD family of debuggers has been produced since the release of the first Flash-based PIC microcontrollers, and the latest ICD 3 currently supports all current PIC and dsPIC devices. It is the most popular combination debugging/programming tool from Microchip.
The REAL ICE emulator is similar to the ICD, with the addition of better debugging features, and various add-on modules that expand its usage scope. The ICE is a family of discontinued in-circuit emulators for PIC and dsPIC devices, and is currently superseded by the REAL ICE.