1. yes, in a number of differnent ways. If you have compatible video files accessible though a webserver on your network, you can access them via the browser and they will start playing. There are also a couple apps that connect to a UPnP media server on a computer for video, photos, music.

2. Both, local network via wifi, and usb to mount the internal sd card (and probably some other cool hacker-type stuff)

wish i could give you an answer on 3, but i'm unfamiliar


I'm a newbie myself (got my 770 this week), but searching on this forum yields a wealth of information.