magento-customer Registration

I'm new to Magento platform & I want to build a customized customer registration page for a company through which employees of that particular compa开发者_如何学JAVAny only can register in my online store with their company email.

So far I'm able to add the custom fields on the registration page by doing some addition in Magento core files. Instead of playing with core files I want to do this by overriding the base classes of Magento. Can someone tell me how can I do this & how can I validate my customer email in a registration page?

Example: I have created an online store for a company called "abc" & the employees of the company can only register to my online store with their company email. Say john is an employee of company "abc" & his company/professional email is "john@abc.com". Here john can only register to my store with the help of his professional email.

How can i do this?

I'm using a 1.5.1.0 version of Magento.

There is a detailed tutorial regarding this please visit

http://www.magentocommerce.com/wiki/5_-_modules_and_development/customers_and_accounts/registration_fields

This will help you almost in every specific need you asked above. If still got question just ask again :)