Two different versions allow you to pick your side.
Activison just announced two Transformers titles for the DS. Taking a page from the Pokemon craze, each version will interact with the other with both local and online features. Appropriately titled Transformers: Autobots and Transformers: Decepticons, each game represents a side of the epic conflict. It's up to the player if they want to be good or evil.
The games will allow you to play as many of your favorite classic Transformers as well as create your own character, choosing colors and vehicles. As you play, the stats and abilities of your custom robot will be improved.
Over local wireless, players can compete with up to three other players in game modes like Team Death Match and AllSpark Sports. There is also some vague information about a mode that takes advantage of the Nintendo Wi-Fi Connection called AllSpark Wars. This mode sounds like a sort of global ranking system where statistics are compiled to see who is winning, the Autobots or the Decepticons.
The game is being developed by Vicarious Visions, who have been known for pushing the 3D capabilities of the DS. So, at the very least, expect the game to look nice. NWR will get some screenshots of the games up as soon as they become available.