Email Accounts for Members

Hello,

I have unlimited email accounts avaiable on my cpanel account, and I know im not going to use that many. so my concept of what I want to do is to provide a free email account to everyone who signs up for my website http://millistacks.com ,  similar to how you can have a facebook email account. For example there email would read istacks@millistacks.com. This will be a additional feature to the already inbox provided by the dolphin software. So what I am looking for is someone who knows how to write a email script that will allow users to sign up for a free email account for my website which will be linked to my cpanel. I hope I have described this correctly and whoever reads this understands the intent clearly. Please reply back for concerns or instrest. Thanks