Word has it that the official MSD (Microsoft Ship Date) of the Xbox 360 Quick Charge Kits is April 18, 2006. Retail price is estimated to be $29.99.
This kit will recharge a single Xbox 360 wireless controller battery in 2 hours, or 2 batteries in 4 hours. A single battery will give you an average of 25 hours playing time.
The kit comes with one battery and is available on preorder from gamestop.com as we speak.
Link: Preorder at Gamestop.com