How can we sent mail content as SMS to Mobile phones using Perl

You'll need an SMS gateway to send SMS.

And i saw in google that there is only 150 characters allowed. Is there any option to send more characters.

Normally your SMS gateway will accept more than 150 & send the content in more than 1 SMS meaning a message that is 200 characters for e.g will be sent out as 2 messages.

How can we sent SMS to other countries also.

Your SMS gateway will allow you to send SMS to (all | most) countries.

Personally I have used both http://Txtlocal.co.uk & http://ClickaTell.com and both were good and easy to use.