Hello I installed Asterisk 1.4.21 and the Voice Mail works fine. I am wondering is there a way to send Voice Mails to users from personal mail instead installing mail server and etc on the server ? Thanks 
You don’t need to install a mail server, as long your server has the Sendmail application, Asterisk will be able to send emails.
In terms of you question.I would suggest that you check /etc/asterisk/voicemail.conf. I think that you will be able to configure Asterisk to send emails using your personal email