Contact form integrated into existing website

I have an existing website running on IIS 6. I need a better contact form script written in ASP using Jmail and Captcha to integrate into the existing contact page, the SMTP server also requires authentication. The form should also check for blank or irregular required fields. The form will be emailed to just 1 email address. Fields on form should be: Name (a required field) Company (optional field) Phone (optional field) Email (a required field, and valid email address) Enquiry (a required field - textarea) Captcha input Submit button When sending the email, I want the contact form to grey out and an animated gif to show please wait... and a success or failure layer on top of the contact form at the end.