Altec Lansing today introduced the inMotion iM500 portable audio system for Apple’s iPod nano. The “lightweight and impossibly thin” speaker system features a built-in iPod dock, a fold-up design, and broad-faced speaker cones with MaxxBass technology. The iM500 is AC or battery operated (six AAA batteries provide more than seven hours of battery life) and also sports an auxiliary jack for using the speakers with other devices. The compact speaker system weighs 12 ounces and folds to a close at 8.5” wide, 0.7” deep and 5” high. The iM500 will sell for $130.