Send emails to other users.

I am using OpenERP for my local usage. I need a clarification, I want to send notification email to other users when a Purchase order is confirmed by Admin user. Please guide me or point me to correct document where I can get the appropriate information. Thanks in advance. Vish **Edit:** When Admin confirms the PO, it is sending the to Supplier automatically. But my requirement is, it has to send to other users created in my ERP system.