Sometimes, while typing, I touch in the touchpad, the pointer moves and the cursor goes to another place in the text. I really hate that. Soo... who to disable the touchpad while typing?

It's simple. In GNU/Linux you can use a small application called syndaemon. With that, you can specify the time between the last key press and the next accepted mouse click.

First, as root, edit the file /etc/X11/xorg.conf, and add, in the Input Device section, the SHMConfig option, with the on value, like this:

Section "InputDevice"
Identifier "Synaptics"
Driver "synaptics"
Option "Device" "/dev/input/mice"
Option "Protocol" "auto-dev"
Option "Emulate3Buttons" "yes"
Option "SHMConfig" "on"
EndSection

Now, save the file and restart the X.Org. The fastest way to restart it is pressing ctrl+alt+backspace (before doing this, make sure that you have closed all applications running and saved any document you may be using).

After that, open a terminal, and type:

syndaemon -i 1 -t -d

The -i switch specify the amount of time (in seconds) between the last key press and the next accepted mouse click (the default is two seconds). The -t switch disables the click and scrolling features. That way, you can still move the pointer. The last switch, -d puts the application running in the background (as a daemon). You can run this command every time you start your session. In the gnome, go to System -> Preferences -> Sessions and add it.