Android secret codes

Cell Battery, WiFi Usage etc Info
*#*#4636#*#* 

Restore Factory Settings
*#*#7780#*#*

Format Phone
*2767*3855# 

Launch service mode
*#*#197328640#*#* 

Test WiFi
*#*#232339#*#* or *#*#526#*#* or *#*#528#*#*

Display WiFi MAC address
*#*#232338#*#* 

GPS test
*#*#1472365#*#* 

Other GPS test
*#*#1575#*#* 

Bluetooth test
*#*#232331#*#* 

Display Bluetooth physic address
*#*#232337#*# 

Start Gtalk monitoring
*#*#8255#*#*

PDA, Phone, H/W, RFCallDate
*#*#4986*2650468#*#* 

PDA and Phone
*#*#1234#*#*

FTA SW version
*#*#1111#*#*

FTA HW version
*#*#2222#*#*

PDA, Phone, csc,
*#*#44336#*#*

Packet Loopback
*#*#0283#*#*

LCD test
*#*#0*#*#*

Melody test
*#*#0673#*#* 
or
*#*#0289#*#* 

Device test such as vibration and lightness
*#*#0842#*#* 

Display touchscreen version
*#*#2663#*#* 

Touchscreen test
*#*#2664#*#* 

Distance sensor test
*#*#0588#*#* 

Display memory version
*#*#3264#*#*