If you are running Ubuntu server edition, then you will likely not be able to run Sublime as it requires some sort of desktop environment (i.e. GNOME, KDE, LXDE, etc.) to function. What you can do is install it on the host OS and set up a shared folder in VirtualBox to allow the VM to access whatever you are writing on the host machine.
If you do indeed have a desktop environment installed, you can double click on the archive and drag the folder out to extract it. If you really want to know the command line command, you can use the following:
tar xjf "Sublime Text 2 Build 2111.tar.bz2"
This will extract the contents into a folder called "Sublime Text 2".