WarioWare: Get It Together! will be launching on the September 10th. With less than a month left, a new trailer and demo have both been launched. The trailer can be viewed below, but the trailer is in Japanese, and demo is currently only available on the Japanese eShop.
While there is no official word from Nintendo, WarioWare: Get It Together! will likely have both the Demo and the Trailer in other regions soon.
Author's Note: ...I keep forgetting that there's a new WarioWare coming out.