You may test ICC profile support with the site “Is Your System ICC Version 4 Ready?”. As you can see it, it display a photo (divided into four sub-pictures, each with a different ICC profile), and this photo must have good colors if the tested software support ICC profiles. You can see under the main photo the different results you can get (from left to right) :

  • software supports version 2 and 4 ICC profiles
  • software supports only version 2 ICC profiles
  • software does not support ICC profiles

If you want to test a web browser, it's easy: just load and display the webpage. If you want to test an image viewer, you have to download each sub-picture then display them with the viewer to test.

The results I get are:

  • Mac OS X 10.4.9
    • Web browser
      • Firefox 2.0.0.6: no ICC profile support
      • Firefox 3.0a7: version 2 and 4 ICC profiles support (open about:config URL, and set “gfx.color_management.enabled” to true)
      • Opera 9.20: no ICC profile support
      • Safari 2.0.4: version 2 and 4 ICC profiles support
    • Image viewer
      • Preview 3.0.9: version 2 and 4 ICC profiles support
      • CocoViewX 0.9.6: version 2 and 4 ICC profiles support
      • The Gimp 2.2.11: no ICC profile support
      • Xee 2.0 : no ICC profile support
  • Windows XP SP2
    • Web browser
      • Internet Explorer 7.0: no ICC profile support
      • Firefox 2.0.0.6: no ICC profile support
      • Firefox 3.0a7: version 2 and 4 ICC profiles support (open about:config URL, and set “gfx.color_management.enabled” to true)
      • Opera 9.20: no ICC profile support
      • Safari 2.0.4: version 2 and 4 ICC profiles support
    • Image viewer
      • System viewer: version 2 only ICC profile support
      • XnView 1.90.3: no ICC profile support
  • Ubuntu 7.04 (Live CD)
    • Web browser
      • Firefox 2.0.0.3: no ICC profile support
    • Image viewer
      • Eye of the Gnome 2.18.1: no ICC profile support
      • gThumb 2.10.2: no ICC profile support
      • The Gimp 2.2.13: no ICC profile support

Of course, ICC profile support is just the first step to get correct color rendering. Second one is to have a well calibrated. With Mac OS X, you may either use “Displays” system preferences or use an hardware calibrating tool to get more precise calibrating. With Windows, you'll have to use an hardware calibrating tool. With Linux and other free Unix, I don't have any idea.