Remote control a computer using another computer
The program you want is Synergy. I personally have used it exactly as you describe.
Here's an explanatory picture from their website:
So you would set up your laptop as the server, and your desktop as a client.
If you have problems seeing the mouse cursor on the far away monitor, I'd suggest you simply increase the pointer size in the control panel.
For minimal configuration, I recommend TeamViewer. It will not log you out like RDC.
VNC: http://www.realvnc.com/