I run an in person game using Roll20 and it works great. We just use 1 laptop (for me, the GM), and the players view the battlemap on a TV connected via an HDMI cord. I log into my account using firefox which I display on my laptop, and then I open an internet explorer window and use that to log into a separate account which I use to display the player's view on the TV. The players describe their movements to me, I make the move on my laptop, and they watch everything happen on the TV. I would recommend getting one of the players to bring their own laptop to connect to the TV, as described in the wiki Aaron linked to. Moving all the tokens is easy, but it's nice to allow the players to scroll around the battlemap on their own.