Hi,
I am a linux n00b and I was wondering which folder is a proper place for installing new software. I want to install jre on my computer and I would like it to be available as a system wide application. Is there a specific place I should install things by convention? Thanks in advance.

Which version of Kubuntu are you using?

Generally
for Breezy see http://ubuntuguide.org/wiki/Ubuntu
for Dapper see http://ubuntuguide.org/wiki/Dapper
for Edgy see http://ubuntuguide.org/wiki/Ubuntu_...

If you have a quick download speed one of the best things you can do is to install Automatix. This is a script which downloads and installs a lot of useful stuff automatically-including JRE. See http://ubuntuguide.org/wiki/Ubuntu_...
(Edgy)

The Java site has instructions and tells you how to install JRE.

Install J2SE Runtime Environment (JRE) - Edgy Eft

As said above you are best off installing it (and other software) with the distros own package management as it makes keeping track and upgrading much easier.

FYI the binary files you actually install (bit like .exe files in windoze) are installed to /bin (for important system stuff like cp, ls, and mount etc), /usr/bin for non-essential programs (like mplayer and gimp). The same goes for programs for root to run and administer the system except the essential binaries go into /sbin (like ifconfig) and the rest into /usr/sbin (like iptables). You also have /usr/local/bin in which machine specific programs and scripts are stored. Sometimes you find precompiled binaries and optional software installed under /opt....you may find java does. All the above can be applied to libraries in locations like /lib and /usr/lib.

Hope that helps. :)

Thanks I got exactly what I needed.
I there a good book for linux that you recommend.

Umm... does anyone know where firefox is installed in kubuntu? I need to know that if I am going to apply the java plugin for firefox.
Thanks.

On this Edgy (pun unintended) Linux machine, it is located within /usr/lib/firefox folder.