Is the white MacBook suitable for software development? I'd like to know if you think the white MacBook (2.26ghz, 2gig ram) is sufficient for software development (using Xcode, Interface Builder etc...)
To elaborate on @Martín's answer, a MacBook is perfectly fine for development, I use one myself and never had issues.

But you could improve it. Switching to 4GB of RAM would be first thing on the list. Using a second screen could also vastly improve this setup. Another (bigger) investment would be to buy a SSD.