Just want to help you guys to find more non-steam servers and enjoy CSS. I've already tried this myself with CSS v61 and it worked very well. However, there are still a few servers that are using older version. But it's not a big deal. Good luck and have fun!  :D

 

 

Instruction:

1. Install Counter-Strike Source
2. Download the Latest Game Patch and install it to your computer.
3. Start Tunngle and join the Counter-Strike Source Tunngle Network.
4. Start the game as your normally would.
5. From the Main Menu Choose "Find Servers" and select the LAN tab.
6. Join any game from the list or create your own.
7. Enjoy!

Download Tunngle here

 

PS: Tunngle Network supports CSGO as well.

trying it out on source right now,

ill let you know how it works out for me.