Comment: Wiring (Score 1) 228
The Wiring platform (from which Arduino is a fork of) is a great option for getting started.
Code wise, It's about 99% the same as Arduino, so all the libraries and code you can find out there is usable, (you just have to tweak the pin numbers)
You can program Arduino boards, wiring boards, AND Atmel chips with the wiring software.
The Wiring S board is slightly cheaper.
And, best of all, the help system is just a lot of commented out descriptions above the code - and it links to a schematic so you know EXACTLY what to build to make the code in the example work.