making my laptop a second monitor

Hi there,   I have a brand new Inspiron 6000.   I was thinking I would like to hook it up to my desktop peripherals so I can access both machines at the same time with my desktop's mouse and keyboard.   I don't want a KVM switch that makes one computer black and the other on, I want to be able to toggle back between both computers and be able to see both monitors at the same time.   I have an ASP application that I need on all the time and it would be great if I could have it on the laptop and use my desktop resources for other things.   What would I need to buy to make this happen?

 

Thanks