Domain Name Availability Checker

I need visitors to one of our sites to be able to check the availability of .com / .[login to view URL] / .net /.org domains and pay us to register them. I need it to work as follows : 1. User Searches For Domain/s (2 text fields domain and suffix) 2. A list of available and unavailable domains are listed 3. User selects available domain/s (check box) and clicks proceed button 4. Price for domain is displayed along with a buy now button 5. User is redirected to paypal to complete transaction