how to re-factor a web site for 3G?

I have a traditional web site which serves users from desktop computer browsers. I am using Microsoft technologies, like ASP.Net, C#, .Net, SQL Server 2008, IIS and Windows Server 2008.

Nowadays, more and more users are using 3G mobile phones, and I am wondering from software perspective, how to add new features to my web site (do I need a client application runs on mobile phone as well?) so that 3G users could have good user experience or new kinds of 3G specific applications? Any recommended documents or real samples are welcome.

For 3G users, I want to distinguish from traditional less-powered and slow network access GPRS mobile phone.

thanks in advance, George

I'd still use ASP.NET for mobiles http://www.asp.net/mobile/

It's more about the usage of the screen than the download speeds.