John said:
Just to add - if the OP does so, he will find the circuit he wants:
http://www.nexusuk.org/projects/vga2scart/circuit
The electronics is trivial - what tends to be difficult is getting the
right software settings to produce a reasonable display. Plus, when you
do so, the result is still disappointing. Many of the settings are not
only critical, but far from obvious to set.
That is why the commercial units do far more in hardware, including
image size adjustment and pan/scroll/zoom functions.
An option that the OP should consider is not to use the laptop monitor
out, but buy a USB2 <>video device. This will both produce as good a
picture on both TV and laptop, simultaneously, but will allow both
screens to be used as they should - eg working on the laptop screen,
whilst using the extended desktop on the TV for things like watching
movies - or simply use as a place to store open documents not currently
being worked on..