Its not actually a phone, it just accesses the internet through wifi, or through a mobile. Touchscreen and instant start-up (from standby mode), so its very handy... 1/2 a replacement for a laptop.
I had a Nokia 770 (predecessor to the N800), and it was one of the best bits of kits I've used in years. Unfortunately, there is a design flaw in them where the screens are breaking ... Nokia don't want to know me now that its broken ... still that said, I'd get the N800 ... but only as long as there are no hidden surprises like the 770 screen problem ...
I've seen them on Amazon for about $300, haven't seen one in any shops here.