The easiest solution is the use the EOS Utilities software that come on the software disk with the Canon cameras. You can then hook up a USB cable to the laptop and use that software to control the shooting in various ways depending on the model/newness of the camera. If your camera has Live View, for example, you can see a preview and make exposure adjustments with that. And, you can choose to either shoot manually or use the "shutter button" interface to take the shot.
You will want to create a folder for the shots that you reference in Utilities and open that folder in Bridge, so that when you take a shot it will "show up".
Lightroom came up with a "tethered shooting" utility with the release of LR3 that works with Canon cameras that doesn't have the Preview and other bells and whistles that the Canon software has but works the tethered shooting in with importing images into the catalog and interface a little more "cleanly" than Bridge. Also, EOS Utilities has a built-in "Work with DPP" interface so that if you wish you can use Digital Photo Professional to quickly view and process Raw files.