How to change the App Pool account of the MOSS web applications.

How to change the App Pool account of the MOSS web applications.
Go to SharePoint Central Administration 3.0 -->
Opertations tab -->
Under Security Configuration select "Service Accounts" -->
For Credential Management select the radio button option Web application pool-->
in the Web Service drop down select Windows SharePoint Services Web Application-->
Under Application Pool drop down select the web application you want to change the Application Pool account-->
Now From the available options specify the parameters of your choice-->
Click "OK"

Then restart IIS as mentioed below:
To restart the application pool, either open IIS and recycle the application pool, or open a command prompt and type iisreset -noforce. Open your SharePoint site in a browser to confirm that the change was successful. This change will be automatically propagated to all web front-ends.