Nintendo announced today that the Wii MotionPlus accessory is going on sale on June 8th for $19.99.
This has been a long wait. Nintendo announced the Wii MotionPlus back in July 2008.

Nintendo Wii MotionPlus accessory for the Wii Remote controller redefines game control, by more quickly and accurately reflecting motions in a 3-D space. The Wii MotionPlus accessory attaches to the end of the Wii Remote and, combined with the accelerometer and the sensor bar, allows for more comprehensive tracking of a player’s arm position and orientation, providing players with a higher level of precision and immersion.
Every slight movement players make with their wrist or arm is rendered identically in real time on the screen, providing a true 1:1 response in their game play.

The Wii Sports Resort game which launches on July 26th, offering a beach-themed follow-up to the groundbreaking Wii Sports game, takes advantage of Wii MotionPlus.
Each Wii Sports Resort game comes packed with a single Wii MotionPlus accessory. With the deep control enhancements of Wii MotionPlus, veteran Wii users and newcomers alike can enjoy unprecedented gaming precision as they cruise on a water scooter, duel with swords, throw a Frisbee and much more. Wii Sports Resort and Wii MotionPlus will be offered together at an MSRP of $49.99.