The Main menu program is also called the alacarte program in Ubuntu. (a la carte is when you order items from the menu in a restaurant, remember?) This program can be installed from the Ubuntu repositories by using its package name alacarte.

Once installed, it can be opened from the Dash by typing Main menu or by typing alacarte at the terminal. It can be used to add, remove or edit application entries from the Dash (like the Start menu in Windows). This includes changing the name, description, command or icon of the application entry.

Tried with: Ubuntu 12.04.1 LTS