It's a while since I did it, but I'm pretty sure there's no installation needed. You just unpack that tar file where you want it to go:
Code:
cd /targetdirectory
tar -xzf /path/to/eclipse-jee-galileo-linux-gtk.tar.gz
... and then you simply execute the eclipse binary contained within the eclipse directory this will have created. There is a little set-up required when you first run it.