Let's Make Robots!

Diecimila, Duemilanove the same or not?

I've been confuse with the arduino which I don't even know if they're the same or not. I'm just asking if they're both the same, like they got the program codes, same instruction like the www.letsmakerobots.com/node/2164 . So all I'm asking Is the arduino duemilanove the same thing as arduino diecmila. If it's yes then I'm good to build my robot project.