Ubuntu provides a simple way to upgrade the software package in deb format. So, if you want to upgrade any applications, you might just type:

sudo apt-get install <application name>

However, sometimes you might find that either you can find the name because it is not inside the Ubuntu list or latest approved version. To skip this, you can go to directly to your System-> Administration-> Software Sources-> Third Party Software and add in this 2 lines

deb http://repository.debuntu.org/ feisty multiverse
deb-src http://repository.debuntu.org/ feisty multiverse

Then goes back to your terminal do the sudo apt-get to get some of the latest released applications. This is how I get my latest Pidgin 2.2.