Sony Ericsson Secret Menu => > * < < * < *
(> means press joystick or arrow keys to the right and mean left)
You`ll see phone model, software info, IMEI, configuration info, sim lock status, REAL time clock, total call time and text labels. You can also test your phones services and hardware from this menu (main display, camera, LED/illumination, Flash LED, keyboard, earphone, speaker, microphone, radio and vibrator tests)

IMEI Number => *#06#

Lock status => < * * <

Shortcut to last dialed numbers => 0#

Shortcut to sim numbers => On main menu, press #

Reset Language => *#0000# or 0000