Hold Alt + N+M+L+L=(Decibel meter)=Displays signals power in decibels instead of bars.
Press V,A,L,D =Address Book file verification= Check the data in your address book.


Hold Alt & Press R,B,L,D=Address Book data structure rebuild=Forces a data structure re-build in the Address Book

Holding Alt and press R,B,V,S=View source code=Display the Webpage source code.

Help Me! menu.
Provides crucial technical information about your device, for when seeking technical
Hold “Alt” and (left) “shift”, then press “H”.
IMEI display.
Displays your device’s international mobile equipment identity (IMEI – your serial number)

on-screen… Also works from all other GSM handsets.
Type “*”, “#”, “0″, “6″, “#” on the Home screen.
“Soft” reset.
Performs a “soft” reset of your device; the equivalent of doing a “battery pull” (ie.

Remove the battery for a few seconds).
Press-and-hold “Alt”, then press-and-hold (left) “shift”, then press-and-hold “Del”.
Event Log.
Displays event logs of all the system-level events that occur on your device…
Hold “Alt” and press “L”, “G”, “L”, “G”.
All of these secrets have been tested on the BlackBerry 8800 and BlackBerry Curve 8300; .
In some cases, you will need to be on the Home screen when you enter these codes…
Various Key shortcuts:
A or C = phonebook
S = search
F = phone profiles
W or B = browser
H = help
K = locks the keys
L = calendar
V = messages
M = messages folder
R = alarm
T = tasks
U = calculator
I = applications
O = options
P = phone
Some new additions thanks to the contributions in this thread:
T – Top of page (in browser)
B – Bottom of page (in browser)
Space – Page down (in browser)
ALT + Right Shift + Del = hard reset
D – Memo pad
U – Switch between hide/unhide in title bar (in browser)
ALT + NMLL = numbers instead of bars for signal strength.