I am sending bulk mail using phplist third party component. But when I am sending above 1000 mail it's taking too much time to send that message. It's taking 4 to 5 hours to send all the mails completely.
Is it possible to reduce the mail sending time? How?
The easiest way is to configure a local smtp server, and have that relay to the "real" smtp server. It shouldn't be taking that long to complete, from code, the email sending. But the time of "actual" delivery is up to the nodes inbetween, and nothing to do with you.
As the previous poster said, configure a local queueing smtp server, if you have shell access to the server. Postfix is a good candidate, it's lightweight and easy to configure. Sending a thousand emails should not take more than a few seconds.
You could use the pear package Mail::Factory as well to specify a lot of options and use various methods of calling the MTA (Mail Transport Agent, i.e. Postfix).