Super Smash Bros. Brawl/Stages

Battlefield
The Battlefield stage is one of the most basic stages in the game and a staple of the Super Smash Bros. series. This time around, rather than floating in a dark void, the level has an ancient ruins theme and floats above a large valley. The time of day changes during gameplay, with the sun rising and setting at regular intervals. The theme is not borrowed from any specific game.

Delfino Plaza
Delfino Plaza has the players fighting on a colorful floating platform that soars above the central hub of Super Mario Sunshine. After a "thrilling landing", the fight takes place in one of several locations on the island, which include the main square and the fountain by the docks. The flightpath follows a repeating pattern.

Halberd
The Halberd stage takes place on a small platform that soars around in the skies along with Metaknight's ship, the Halberd. It is not clear to what extent the Halberd has on gameplay, but the platform was seen to dock on it at once point.

Lylat Cruise
This stage actually appears in the trailer where Fox is confirmed. The name of the ship is Pleiades.

Mario Kart
The Mario Kart level is a lot like the Mute City level from Super Smash Bros. Melee. It involves characters flying over a race track and doging Shy-Guys  driving Go-karts. This level has been confirmed, but may change later in the development of the game.

Pokémon Stadium
The Pokémon stadium is very similar to the Super Smash Bros. Melee level. While the background has been changed a bit, it still has two small floating platforms over the giant Pokéball.

Yoshi's Island
The Yoshi's Island stage has players battling on a stage that changes seasons. This level will probably change dramatically before the release of Brawl.