To install the latest version of VLC read this article

For those who like to test the latest Alpha release of 10.04 here's is a guide to install VLC (using motumedia ppa)

First you need to install the medibuntu-keyring, w32codecs and libdvdcss2 to do this open a Terminal (Applications->Accessories->Terminal) and copy+paste the following lines:

sudo wget --output-document=/etc/apt/sources.list.d/medibuntu.list http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).list && sudo apt-get --quiet update && sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring && sudo apt-get --quiet update

sudo apt-get install w32codecs

sudo apt-get install libdvdcss2

To add the motumedia GPG key copy+paste the following line:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys  C5D7718106438B87

To install the ubuntu restricted extras package, copy+paste the following line:

sudo apt-get install ubuntu-restricted-extras

Then add this line to your repository, go to System->Administration->Software Sources and select the Third-Party Software tab then click the Add button and copy+paste the following line:

deb http://ppa.launchpad.net/motumedia/ppa/ubuntu lucid main 

To instal VLC open a Terminal (Applications->Accessories->Terminal) and copy+paste the following lines:

sudo apt-get update

sudo apt-get install vlc mozilla-plugin-vlc

sudo atp-get upgrade 

When installed you can find VLC under Applications->Sound & Video