You can use Zend libraries outside of the framework but they do have dependencies, IE you can't just use the mail library separately. Take a look at composer http://getcomposer.org/. It is a package manager for PHP and installs the required dependencies for various packages automatically such as YUM.
https://packagist.org is the website that hosts these packages available for download, take a look at the Zend Mail library. There are other Zend libraries on their as well, just search Zend.
https://packagist.org/packages/zendframework/zend-mail
If you are struggling to grasp the concept mentioned above take a look at this tutorial:
http://net.tutsplus.com/tutorials/php/easy-package-management-with-composer/
So with composer installed, to download the Zend Mail library with all its dependancies use this composer.json file.
{
"require": {
"zendframework/zend-mail": "2.3.*@dev"
}
}
After running composer update it will produce a folder called vendor that holds all your libraries (in this case only Zend Mail and its dependencies). There will be a special file named autoload.php in the root of this directory.
To actually use the library within your code use
include_once 'vendor/autoload.php';
If you want to download the whole library without the MVC application go to http://framework.zend.com/downloads/latest and select "Zend Framework Minimal Package", here is its description:
Zend Framework Minimal Package
Download a minimal package from zend.com's CDN. Contains only the
components in the Zend Framework Standard Library. (Requires
registration)
Hope that helps.
