thinkpad T23 power settings

[znokia]

hello, totally new user, brief history and question:

installed today on an IBM Thinkpad T23, reformatted 40gb HB, system has 1024mb RAM, default Savage/IX display
selected default desktop/laptop installation and all went well

the only change I've made is display settings to 1024*768

how may I enable laptop on standby when I close the lid? (please do not assume any technical knowledge, so explain so that a 4-year old would understand)