just connect the VGA cable to your laptop. nearly all laptops come with a VGA port, some are beggining to come with DVI ports too.
depending on the graphics card you have should tell you what resolution is supported and if your monitor has that resolution supported, your good.
i have a sony vaio with intel GMA 950 onboard video, and i run it dual screen with my 22 inch no problem.
theres no special cables needed or whatever, just take the VGA cable supplied by your monitor and connect it to your laptop and configure the resolution and graphic settings, whether or not you want dual screen, single display, etc. (if your card supports dualscreen of course,which pretty much all do now.)