Adobe Gamma is the most well know, and is a utility that gets installed if you have a copy of Photoshop or Photoshop Elements. It's more accurate than comparing a print to the screen, but it still suffers from the same drawbacks. Namely, ambient light falling onto your screen and your eyesight (if you don't use Photoshop or Photoshop Elements, then there's also the other drawback in that you can't purchase it seperately).

Have a look at this guide to see how Adobe Gamma works. The software leads you through setting the contrast and brightness, and then the gamma. The one thing that takes it up a notch is that it creates an ICC Colour profile for your monitor based on your settings. This can then be saved and set as the default profile for your monitor, and will be used every time you use your computer. Altogether, it's an effective way to get a reasonable level of accuracy with a minimum of fuss. However, as with print matching, do note that if your monitor is not all that linear in displaying colours (such as with an older, or poorer quality monitor), then this software still cannot make any adjustments for this and you might well get colour casts in certain areas.