New to linux (Ubuntu) how to install new video card?

Right now Im using the onboard video card. But I have no clue on how to add the video card so that it works with ubuntu? I did know if it works such as plug and play or i need to add the drivers first before installing the pci card... please help me....

add the card, plug the monitor and run:
sudo dpkg-reconfigure xserver-xorg
choose the driver, resolution and screen size ussually you can let the default options for the other questions)

Thanks Sebastian... this helps me too but a supplementary Q?

If the card is dual-monitor (Matrox Millenium P750) and both dual screens are connected (BenQ FP202W) is your above answer still the same?
Matrox does have specific Linux drivers for this card (http://www.matrox.com/graphics/en/corpo/support/drivers/driverList.php) but how would i go about installing that driver (i'm new to Linux too)

Thanks
vajras

As it says on the matrox site, just a correction for ubuntu about sudo:

Download to Desktop, start terminal and run these commands:
cd Desktop
sudo -s
sh matroxdriver-x86_32-1.4.4-installer.run

But they look terrible old. Maybe not working with new xorg.

Thanks Anders for your prompt reply and, yes i too saw that they are a bit dated (July last year)

i have downloaded and printed both the Matrox Readme files

But... i also found this later driver version on the "Unofficial Matrox Technical Support Forum" between posting here and your reply ;)
http://matrox.tuxx-home.at/viewtopic.php?t=217

So ... which of the following install commands will i need to use?
{i have either a Mandrake Spring 2007 or Ubuntu 7.04 distro to install}

"Making it executable"
or
"Call it as argument of your default shell"
or
"On systems, where sudo is used, the following syntax works"

will i need to use

[quote]... When you download the file, as I said above, it will _NOT_ be executable
therefore the following command does not work.

Code:
./matroxdriver_mga-x86_32-4.4.3-installer.run

You could now either make the file executable or circumvent this issue
by calling it as argument of your default shell:

Making it executable:

Code:
chmod 755 matroxdriver_mga-x86_32-4.4.3-installer.run

Call it as argument of your default shell:

Code:
sh matroxdriver_mga-x86_32-4.4.3-installer.run

On systems, where sudo is used, the following syntax works:

Code:
sudo sh matroxdriver_mga-x86_32-4.4.3-installer.run
[/quote]

bump

i can't enabled desktop effects,when i click to turn on desktop effect,my screen is go to the white screen,so i can not enabled desktop effects.