T-Mobile Sidekick 4G official Pictures. T-Mobile Sidekick 4G is a Smartphone of t_mobile. The T-Mobile Sidekick 4G Android Smartphone. Announced Mar 2011. Features 3.5″ Display, Hummingbird Chipset, 3.15 MP Primary Camera, 1500 MAh Battery, 512 MB RAM. T-Mobile Sidekick 4G price starts.