To see IMEI
press *#06#

To see software version
press *#9999#

To set screen contrast
press *#0523#

To see speed, voltage and battery temperature
press *# 0228#

Software version: *#9999#
IMEI number: *#06#
Serial number: *#0001#
Battery status- Memory capacity : *#9998*246#
Debug screen: *#9998*324# - *#8999*324#
LCD kontrast: *#9998*523#
Vibration test: *#9998*842# - *#8999*842#
Alarm beeper - Ringtone test : *#9998*289# - *#8999*289#
Smiley: *#9125#
Software version: *#0837#
Display contrast: *#0523# - *#8999*523#
Battery info: *#0228# or *#8999*228#
Display storage capacity: *#8999*636#
Display SIM card information: *#8999*778#
Show date and alarm clock: *#8999*782#
The display during warning: *#8999*786#
Samsung hardware version: *#8999*837#
Show network information: *#8999*638#
Display received channel number and received intensity: *#8999*9266#

*#1111# S/W Version
*#1234# Firmware Version
*#2222# H/W Version
*#8999*8376263# All Versions Together
*#8999*8378# Test Menu
*#4777*8665# GPSR Tool
*#8999*523# LCD Brightness
*#8999*377# Error LOG Menu
*#8999*327# EEP Menu
*#8999*667# Debug Mode
*#92782# PhoneModel (Wap)
#*5737425# JAVA Mode
*#2255# Call List
*#232337# Bluetooth MAC Adress
*#5282837# Java Version

Type in *#0000# on a Samsung A300 to reset the language
Master reset(unlock) #*7337# (for the new samsungs E700 x600 but not E710)
Samsung E700 type *#2255# to show secret call log (not tested)
Samsung A300, A800 phone unlock enter this *2767*637#
Samsung V200, S100, S300 phone unlock : *2767*782257378#