How to install third party softwares?

Is it a ".deb" file?

The native package format for Ubuntu is ".deb" debian packages. Normally the best way to install these is transparently via the package manager Synaptic. Alternatively you should download (or otherwise obtain) the .deb package directly, you can then install it by double clicking it to open it and then clicking "Install" to install it. Note if the package has dependencies that you don't have on your system you'll need to have those packages also or have a connection so the system can download them for you.

Lastly you get the equivalent of zip file style packages, which you should prefer not to use as installing them is more fiddly/harder work.

VLC is in the standard repositories, so either install it directly, or get the package and it's dependencies and copy it onto you PC and install as I described above. You can directly obtain packages from http://packages.ubuntu.com/

See here: http://packages.ubuntu.com/intrepid/vlc

((How can i install softwares from add/remove programs without an internet connection?))
Is an more advanced task, dont use add/remove,
use Synaptics to install programs without an internet connection, is very easy,
use Synaptics just like you are On Line, but DONT press " Apply " button,
go to menu:
File--->Generate Package Download Script...

Name it " myscript.sh " (for example, name doesnt matter...)
Save this generated File to USB Pendrive (for example, or other removable media...),
run it on a PC with Internet connection, it will download all packages of your program,
copy the packages to the USB Pendrive, plug it on the PC without Internet connection,
open Synaptic, go to menu:
File--->Add Downloaded Packages...
Search for the packages on the USB Pendrive, Synaptic will install the program.

Inside the Generated Script " myscript.sh " you have Direct Links to the packages,
so it can be used in a PC running Ubuntu, MS Windows or OS X.

((When will be the next version of Ubuntu released?))
04 / 2009

If you are still having trouble with this then please post it as a new question. Only the most recent questions tend to get looked at so posting/reposting a question just before america arrives online after work/school gives the best chance of getting a good few answers.
https://answers.launchpad.net/ubuntu/+addquestion

If the problem has been resolved then please follow the link to the forum thread and mark it as Solved.

Good luck and many regards from
Tom :)