The software (IDE) for Arduino and Wiring is fairly similar, with both supporting, or able to support more or less the same functionality. If you are trying to decide which platform to use, I would look mainly the functionality vs. cost of the boards. Arduino is cheaper but less powerful (e.g. fewer pins, less memory). It does, however, have the advantage that the atmega8 chip can be easily removed and placed in a PCB or prototyping board for a PCB. The Wiring board is good if you need complex programs or lots of pins, but it costs more and you need one for each project.