I use ScreenMonkey for non-d20 games and Fantasy Grounds for my d20 games.
Most, if not all, Virtual Tabletop (VT) tools have some sort of "fog of war" where you, as a player cannot see the entire map.
Examples
DM View
Player View
Combine with Skype and it's almost like you're there.
If any Paizo person would like to see this in action just email me at fatogre@fatogre.net. All you need is a web-browser, a microphone, a free Skype account and a little time.
I plan on running games for Pathfinder as an example in this thread on Fantasy Grounds
Later,
Greg Volz