Run LAN games over internet - VPN
 

Follow the instructions below to connect to the VPN.
Once connected you can play LAN games over the internet.

Hosted on the vpn is our Counter strike 1.6 (legit and non steam) & Call Of Duty 2 100mbps server.
Call of Duty 2, we also play C&C Generals, Red Alert 2, dungeon keeper 2 and most are hosted frequently.

You can also create your own game servers as you would for a LAN party.

To join the network:
1.Install Java
2. Install TAP-Win32 from OpenVPN De-select all components apart from "TAP-Win32 Virtual Ethernet Adapter" (win2k/XP: open network connections click advanced and put the new adapter to the top of the list)
3. Download P2PVPN here: P2PVPN
4. Unzip the file, launch the included P2PVPN.exe (Run as Admin for vista users)
5. Click settings give yourself a name and change listening port to 51000.
6. Download this file and save to documents folder: VPN Invite
7. click Accept Invitation and load the file you just downloaded.

It may take a few mins to connect to the VPN, once connected you will be able to see all other users in the VPN, To join or create a new game just do as you would for a LAN (local network) game.

You can also use the chat box on p2pvpn to arrange matches between users.

For more info click here.

I'd have to suggest Hamachi for ease-of-use for the majority of people. And from having it used it extensively myself in the past. No need to make it more complicated than it needs to be, especially for people new to this stuff.

http://logmeinwiki.com/wiki/Hamachi:Gaming_over_Hamachi

Once I wanted to try Hamachi but then gave up as soon as I saw they want me to register myself (and my PC's, too?) on their site blabla...

Yeah that is a downside and, admittedly, they have stepped that up a little recently. But it's all OK. It's all free and there aren't any trust issues with the company. I've used their other products for remote administration in the past, so I had no problem trying out Hamachi. I guess it depends what you want to do with it. RTS's and strategy games are fine through it, but due to the inherent latency-increase, I would avoid it for FPS's.

True, true, I have nothing against DynDns.org which, from this point of view, works pretty similarly... ;)

Check tunngle :P
You can play all games that support lan with allot of people.

Call of Duty 2, we also play C&C Generals, Red Alert 2, dungeon keeper 2 and most are hosted frequently.