[Vivtek]

Your iPad has a browser. That browser runs HTML5 and JavaScript. That's the quick way to get to something programmable. If you want to get down and dirty, drop thirty bucks on an Arduino.

Personally, I think the post-PC era is going to be even more awesome.

[wanorris]

Totally agree on the browser.

But as an aside, can you program an Arduino if all you have is an iPad? Or would you have to go buy a general-purpose PC for somewhat more than $30?

[Vivtek]

I could program an Arduino with a pair of tweezers, son.

...

Seriously, I have no idea. I suppose Apple's too cool for USB ports, but maybe Wifi? That ups the cost of your Arduino setup, it's true, but still - there has to be something you can do to communicate between your iPad and your Arduino that doesn't involve a general-purpose machine in between.

[wiredfool]

There's now a blessed serial cable with a dock connector, and some form of an arduino programming environment on the iPad. The only drawback is that the cable is more expensive than the arduino.