If you have Nokia N900 mobile phone and ever try to looking found Nokia N900 User Guide at the Nokia services, you should hard to find away because the provide link is actually broke, move, or disable.
That was really disappointing as Nokia N900 User Guide is very useful.

Here are some most useful guides for Nokia N900:

Some Short Cut Keys:
Ctrl + C: Copy text
Ctrl + V: Paste text
Ctrl + X: Cut text
Ctrl + A: Select all
Ctrl + Right arrow: Move the insertion point to the end of the word
Ctrl + Left arrow: Move the insertion point to the beginning of the word
Ctrl + Backspace: Bring you back to the visual task manager if you are in one app program.

Smart Dialing
Just type the name you aim and the contact will appears and start filter that name

Circle zooming
Double tap on a text will zoom it. You also can do it by spinning the finger clockwise. As for spinning it counterclockwise will zoom out.

Light Color Sign
N900 has the notification through the light color on its upper left corner, by seeing the color appear you can get the results:

- Orange means battery charging
- Green means battery full
- Blue means app triggered app such as receiving email, text, or IM

However, if you want to see Nokia N900 User Guide more you can get it here