I like little lappies anyway--my current one is a Dell 700n, and I only got it instead of a smaller one because the smaller ones were twice as expensive.
It will be a pleasant downgrade from the ginormous 17" PowerBook I've been lugging around for the past 4 years.
Other than that, I'm not sure, but I'll definitely be interested to try it.
I do think it's a great idea, but I imagine it would be very overwhelming for a kid who has never used a computer before, let alone programmed (in a foreign language, too, most likely).
What would be really neat was if in addition to opening the source, it also had some sort of dynamic tutorial that would explain what the kid was looking at. For example, they open up a webpage and it explains the HTML to them.
Someone on #olpc on irc.freenode.net mentioned it a couple days ago. I do think they're still working on it, it's just not going to be ready right away.