There may be a case where you want to kick start a particular application or script as soon as you login into your Gnome desktop. For example I want to run "Avant Window Navigator" every time I login into my Gnome.
Here is the way to do this....
Go to Gnome contor center by using command: gnome-control-center
This should open up the control center from where you can manage your personal desktop settings
Now go to group "System" and select "Session" this should open up the windows where all the start up applications are listed, click on "Add" to add or browser to your application or script to get executed every time you login to Gnome