Nautilus-Terminal Plugin for Nautilus, Install it in Ubuntu/Linux Mint

Install Nautilus-Terminal Plugin in Ubuntu 12.10/12.04/11.10/11.04/10.10/10.04/9.10/ Linux Mint 14/13/12/11/10/9/8/ and Other Ubuntu Based Distributions

Nautilus Terminal is a plugin for Nautilus, it always open terminal in Nautilus at current folder, and follows the navigation (like an automated "cd" command). This plugin also supports drag and drop folders and files.
It is possible to hide and show terminal via this shortcut - F4
If you don't want to install this plugin, there is alternative for you called Sunflower. Sunflower is twin-panel file manager.

To install Nautilus-Terminal in Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:

Terminal Commands:
sudo add-apt-repository ppa:flozz/flozz
sudo apt-get update
sudo apt-get install nautilus-terminal

Now restart nautilus

Terminal Command:
nautilus -q

That's it

Source: Nautilus-Terminal