There are a total of 8 cabinets, 2 in each district. Until someone comes up with a video or picture guide, here's a list of where all 8 are.
Edit: Here's a video that I clearly didn't make showing where they are.
District 1 - Ingleton
Round 2: As you begin, in front of you to the left is a diner where you can run through to get one of the generators. The Street Fighter cabinet is inside by the back door.
Round 4: In Uncle Bill's Buffet, the 1942 cabinet is inside on the wall back a bit on the left.
District 2 - Central City
Round 1: Towards the end of the level, before you get to the boat, on the left is an alcove where you have to climb up the left side into a safe zone. The Captain Commando cabinet is in the safe zone.
Round 4: Run (or take a vehicle) all the way down the street to the end by the beach. Turn right. Next to the entrance to the hotel is a coffee shop. The Ghosts and Goblins cabinet is inside.
District 3 - Sunset Hills
Round 1: Along the route to the street, after the subway tunnel, the Darkstalkers cabinet is in the room right before you go out to the street to defeat the bikers. In fact, right as you get to the cabinet, the game should tell you to defeat the bikers. The cabinet is on the right side before you go outside.
Round 2: In the Bite the Bull steakhouse where one survivor is found, the Power Stone cabinet is located right next to the survivor. If you go into this building from the back, up the stairs, you'll see it right when you get to the survivor.
District 4 - South Almuda
Round 1: Turn left from the start instead of going into Rocket's Red Glare. Fight through the zombies toward the supply caches, and on the right is Bob's Tires. The Rival Schools cabinet is inside.
Round 4: As you look for the bombs, you'll need to go into Speedy G's strip club. The Final Fight cabinet is straight ahead from the front door as you go in. (The bomb is on the table to your left.)