New hardware features: GPS, sliding keyboard and a 400MHz CPU (specs. from Engadget). The device is a little smaller then the N800 (which I think is nice). The software is called OS2008 (who would have guessed?). They finally kicked out Opera and use a Gecko-based browser (see my older blog entry).
Another interesting thing for N800 owners is the fact the Nokia announced a OS2008 version for the N800. This means people who don't like to buy a new device will be able to get all the new eye candy for free. This basically is possible because the N800 and N810 hardware is very similar.
I'm really looking forward to the N810. For me as a Linux (shell) hacker a hardware keyboard will be extremely interesting. The N810 is supposed to by sold starting mid November.