Hi, I have 10 years experience in software design and development, experience in C++,C# 2.0/3.5/4.0 and web applications
(Javascript, CSS, HTML, Asp.Net, SOAP, AJAX, IIS 6.0/7.0/7.5), MS Sql 2000/2005/2008.
I suggest Windows Asp.net technology (IIS 7.5) - forms authentication with cookie support, so that users can automatically login using cookies. Other functionality we can discuss later.
Best regards