Michael,
I use a ColorVision Sypder 2 Express for calibrating my CRT monitors (Yes CRTs are obsolete but they are better at rendering colours and have true blacks) for photography work.
They have to be profiled every month as screens will vary in color representation over time.
If you are using a laptop screen, consider getting a separate screen for doing processing, has nearly all laptop screens are useless at presenting a gamut of colours
The Spyder 2 series has been superseded by the Sypder 3, you can get a Sypder 3 Express from about €80 or the Sypder 3 Pro from €140 from Dabs.
www.dabs.ie/products/colorvision-spyder3-pro-4XT0.html?q=spyder
The Sypder 3 Express should be fine for most of your needs if you are using a single monitor system.
Here is a tutorial I wrote on monitor calibration -
www.offshoot.ie/tutorials/56-colour/59-monitor-calibration
If you do decide to go down the route of colour management, there is more to it than just monitor calibration, you need to look at the colour space of all your equipment and processing software and even how you output your end result.
For me doing photography work, my camera is setup to use Adobe RGB 1998 colour space, so is Lightroom and Photoshop and when I decide to output an image to the web I need to change the colour space to sRGB as very few browsers are colour aware and most sites like flickr will change the colour space to sRGB.
This is the best resource on colour management:
www.cambridgeincolour.com/tutorials/color-management1.htm
Hope some of this helps
Darragh
  