Setup Runlevel to 3 for Ubuntu 12.04

[Dhimant]

Hello,
I am new to ubuntu but i have used linux previously and know some commands of it.
I want to set my Ubuntu Desktop machine as "Multi-User mode,Network Support, console logins only, with all services and not GUI" to reduce memory consumption.
Please direct me which files need to be changed to achieve that .
Thanks in advance.

[dino99]

http://askubuntu.com/questions/74645/possible-to-install-ubuntu-desktop-and-then-boot-to-no-gui

http://superuser.com/questions/310978/starting-ubuntu-without-the-gui