TeamViewer is a free tool that makes it incredibly easy to set and use a VPN connection; a Virtual Private Network that lets you take complete control of another PC from your own computer, whether they're separated by a soda can or a continent (and as long as both machines are running TeamViewer). It enables two-way connections in which users can flip control back and forth. TeamViewer also lets you hold virtual meetings with multiple participants (again, they all must have TeamViewer installed).
With a name like TeamViewer, you'd expect it to be an enterprise-ready tool, and you'd be right: TeamViewer's robust simplicity is what happens when multiple users of vastly different skills need to use software. After a while, the bugs get squashed pretty firmly. But TeamViewer is free to non-commercial users. That means you can use it to access your work and home PCs remotely.