Nokia has released more information about the N78 since the press release came out. The press release made it sound like a younger sibling to the N82 but this younger sibling has a few unique characteristics of his own.
First up, it will come with a rather unique button layout. Rather than the traditional 12 keys, it will have four elongated with illuminated key labels. It definitely could take some getting used to!
European and North American versions have both been announced, the former with 900/2100MHz bands HSDPA and the latter with 850/1900MHz HSDPA bands. Both will have quad-band GSM/GPRS/EDGE. The N78 will also come with 70MB of internal storage, A-GPS, a 2.4-inch QVGA display, an FM transmitter that can broadcast music to other devices (like your car radio), 802.11 b/g Wi-Fi, Bluetooth 2.0+EDR, a 3.2MP camera with Carl Zeiss optics and a microSD expansion slot. It will be available in aqua, brown or white.
The N78 will be available in the second quarter for 350€ or about USD$500.