CoD4 is still a lot of fun. Plenty of people still play it, and most of the servers have more then enough players to play properly. I can join my favorite server in 10 sec.
Click on "Multiplayer" and select "Play Online". Choose the game mode you want to play and click on "Find Match". Wait for the game to search for available servers. Once it's done, it will show you a list of servers that are available for your region.
