I think there is a huge opportunity here for teaching. But it depends on the demographic that we're talking about.
For adults, there is already a wealth of places to learn about computer science out there for those with the the means. Seriously, tonnes. Huge amounts of free languages, code, books, tutorials etc. Heck, there are free university courses online from Stanford and MIT on iTunes (see http://ocw.mit.edu/index.htm
For kids, its a totally different problem. Many don't have a computer and can't afford one. The Raspberry Pi will change everything in that regard. Its a school supply, a gift, or something they could buy with an allowance.
The next big problem isn't about the accessibly of information, it's a problem of approachability. It's a hard topic to get into because, typically, there is so much you need to know up front before you can do anything. You need to learn about files, folders, installing a language/compiler/ide, editing source, building, reading compiler messages, executing, setting up a project (or using a command line), etc. That's the easy stuff and its already a complex process for a kid.
It wasn't always like that. I started programming in Basic when I was 5 on a Commodore Vic-20. I remember making programs that drew ascii pictures and debugging problems when it didn't look right. It wasn't because I was some kind of prodigy; It was because it was simple to use. If a kid can read, then they can program. It's as simple as that. Logo was another good example of this.
But since then, the development process has only gotten more complex even for the "easy" systems. Also, the first things that kids want to do isn't the easy stuff, the first question is how do I draw something on the screen, move it around, and play sounds. You need an environment where they can get to those things in their very first sitting before they lose interest. If I wanted to teach a kid to program today, I'm not sure the options have gotten any better in the last 30 years.
My goal is to change that. I think that the "love" engine based using lua is a great place to start and I'd like to get it ported to the Pi. It's already in the low-teen-friendly area but I'd like to polish it a bit more and make it into something that could be tackled by an 7-8 year old.
I'd love to see a programming environment targeted at kids in the out-of-the-box distribution.