I have a software installed in ubuntu in my PC. Can i make a .deb or .tar.bz2 file of this software from here so that i can install this software in another machine without having internet connection?
You can find the .deb files of packages that you have installed in the folder /var/cache/apt.
If you had another Ubuntu machine with the same version, you could copy over the contents of /var/cache/apt to that machine and then try to run sudo apt-get install packagename and it would try to pull them from the apt cache. I would definitely not recommend this unless you are using the same version of Ubuntu on both machines.