Yes, VNC is the way to go.
Download
Chicken of the VNC and put it in your Applications folder. This lets you control other Macs.
Go into System Preferences...->Sharing and turn on "Apple Remote Desktop" in the "Services" tab (you'll need to specify access privileges, and, in particular, a password). If your firewall is on, you'll need to go to the Sharing->Firewall tab and add a new rule ("New...", Port Name->Other, call it "VNC", and open up port 5900). This sets up your Mac to be controlled.
If you have a network router, you'll need to tell it to send traffic on port 5900 to you Mac's IP (intranet IP, like 192.168.1.xxx) address. This forwards VNC traffic to your Mac when it is to be controlled.
Use a service like
DynDNS to create a domain name others can access (like myname.homeip.net). This lets people find your internet IP address.
If you and your friends all do this, you can, using Chicken of the VNC, remotely control each other's Macs. To disable it, just go into the Sharing preferences panel and turn off Apple Remote Desktop.