This is the requirement of all the people in my college and many others. Initially it was a big problem for me also but later I was able to resolve it.
Additionally you can take a look on http://www.google.com/linuxrepositories which I have noticed just now and it actually explains you how to add repositories to a Linux system.
What is a repository?
This is a question asked to me by several people. Repository is a database which stores rpms, debs etc which Linux users use to install packages on a Linux system.
How to add a repository?
Refer to the above link for adding repositories. Some good repositories are Packman for openSUSE and Livna for Fedora, see this video .
People in NIT Durgapur can add Packman fromhttp://10.0.0.150/?q=node/30 or check out the list of all repositories available at http://en.opensuse.org/Additional_YaST_Package_Repositories .
How to install a package?
In openSUSE go to Yast > Software search whatever package you want and install. Also you can use the advanced 1-click install feature of openSUSE (most easy to use). Search the packages at Webpin http://software.opensuse.org/search and then install them using 1-click feature.
In Fedora you can use
#yum install <package> from the command line.
How to listen to mp3 and watch avi files?
You can either install VLC from http://www.videolan.org/vlc/download-suse.html and or search mplayer at webin and install it for openSUSE.
For fedora, VLC is available at http://www.videolan.org/vlc/download-fedora.html. Just follow the instructions there.
How to compile C/C++, Java programs?
Gcc is the compiler for C/C++ , java.
Write the c program in a text editor on Linux gedit or kwrite or VI. Then compile from the command line
Then run the program
Netbeans is also available for Linux.