Sony Ericsson Secret Menu: -> * <- <- * <- *
(-> means press joystick, arrow keys or jogdial to the right and <- means 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#
Lockstatus: <- * * <-
Shortcut to last dialed numbers: 0#
Shortcut to sim numbers: On main menu type a number and press #

If you change the language from default to any other language, then it may be difficult to switch to default language. The shortcut is very simple. Just press < 0000 > . < stands for left arrow button or joystick and > stands for right arrow button or joystick.