When I buy a Roku, how many Tvs can hook up to it? Or do I need one Roku per TV? If multiple, can I watch on both at the same time?
Technically you can connect the Roku to as many TV's as there are outputs -- and even more if you use switches/splitters. Practically, you need to run cable from the Roku to the TV via component, composite, HMDI, etc. The remote is also an IR remote, so you'd either need to use wifi remote (i.e. iphone App) or some kind of RF to IR remote to control a Roku that's not in-room/in-sight.
All outputs on the Roku are on at once, so you could technically run, for example, HDMI to one TV and component to another and watch the same thing at the same time. You couldn't watch 2 different things on 2 different TVs with 1 Roku though.